岑永洪

XML Schema Part 2: Datatypes Second Edition

W3C Recommendation 28 October 2004

This version:: http://www.w3.org/TR/2004/REC-xmlschema-2-20041028/
Latest version:: http://www.w3.org/TR/xmlschema-2/
Previous version:: http://www.w3.org/TR/2004/PER-xmlschema-2-20040318/
Editors:: Paul V. Biron, Kaiser Permanente, for Health Level Seven; Ashok Malhotra, Microsoft (formerly of IBM)

Please refer to the errata for this document, which may include some normative corrections.

This document is also available in these non-normative formats: XML, XHTML with visible change markup, Independent copy of the schema for schema documents, A schema for built-in datatypes only, in a separate namespace, and Independent copy of the DTD for schema documents. See also translations.

Abstract

XML Schema: Datatypes is part 2 of the specification of the XML Schema language. It defines facilities for defining datatypes to be used in XML Schemas as well as other XML specifications. The datatype language, which is itself represented in XML 1.0, provides a superset of the capabilities found in XML 1.0 document type definitions (DTDs) for specifying datatypes on elements and attributes.

Status of this Document

This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at http://www.w3.org/TR/.

This is a W3C Recommendation, which forms part of the Second Edition of XML Schema. This document has been reviewed by W3C Members and other interested parties and has been endorsed by the Director as a W3C Recommendation. It is a stable document and may be used as reference material or cited as a normative reference from another document. W3C's role in making the Recommendation is to draw attention to the specification and to promote its widespread deployment. This enhances the functionality and interoperability of the Web.

This document has been produced by the W3C XML Schema Working Group as part of the W3C XML Activity. The goals of the XML Schema language are discussed in the XML Schema Requirements document. The authors of this document are the members of the XML Schema Working Group. Different parts of this specification have different editors.

This document was produced under the 24 January 2002 Current Patent Practice (CPP) as amended by the W3C Patent Policy Transition Procedure. The Working Group maintains a public list of patent disclosures relevant to this document; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) with respect to this specification should disclose the information in accordance with section 6 of the W3C Patent Policy.

The English version of this specification is the only normative version. Information about translations of this document is available at http://www.w3.org/2001/05/xmlschema-translations.

This second edition is not a new version, it merely incorporates the changes dictated by the corrections to errors found in the first edition as agreed by the XML Schema Working Group, as a convenience to readers. A separate list of all such corrections is available at http://www.w3.org/2001/05/xmlschema-errata.

The errata list for this second edition is available at http://www.w3.org/2004/03/xmlschema-errata.

Please report errors in this document to [email protected] (archive).

Note: Ashok Malhotra's affiliation has changed since the completion of editorial work on this second edition. He is now at Oracle, and can be contacted at .

1 Introduction
    1.1 Purpose
    1.2 Requirements
    1.3 Scope
    1.4 Terminology
    1.5 Constraints and Contributions
2 Type System
    2.1 Datatype
    2.2 Value space
    2.3 Lexical space
    2.4 Facets
    2.5 Datatype dichotomies
3 Built-in datatypes
    3.1 Namespace considerations
    3.2 Primitive datatypes
    3.3 Derived datatypes
4 Datatype components
    4.1 Simple Type Definition
    4.2 Fundamental Facets
    4.3 Constraining Facets
5 Conformance

Appendices

A Schema for Datatype Definitions (normative)
B DTD for Datatype Definitions (non-normative)
C Datatypes and Facets
    C.1 Fundamental Facets
D ISO 8601 Date and Time Formats
    D.1 ISO 8601 Conventions
    D.2 Truncated and Reduced Formats
    D.3 Deviations from ISO 8601 Formats
E Adding durations to dateTimes
    E.1 Algorithm
    E.2 Commutativity and Associativity
F Regular Expressions
    F.1 Character Classes
G Glossary (non-normative)
H References
    H.1 Normative
    H.2 Non-normative
I Acknowledgements (non-normative)

1 Introduction

1.1 Purpose

The [XML 1.0 (Second Edition)] specification defines limited facilities for applying datatypes to document content in that documents may contain or refer to DTDs that assign types to elements and attributes. However, document authors, including authors of traditional documents and those transporting data in XML, often require a higher degree of type checking to ensure robustness in document understanding and data interchange.

The table below offers two typical examples of XML instances in which datatypes are implicit: the instance on the left represents a billing invoice, the instance on the right a memo or perhaps an email message in XML.

Data oriented	Document oriented
1999-01-21 1999-01-25 Ashok Malhotra 123 Microsoft Ave. Hawthorne NY 10532-0000 555-1234 555-4321	Paul V. Biron Ashok Malhotra Latest draft We need to discuss the latest draft immediately. Either email me at mailto:[email protected] or call 555-9876

Data oriented

Document oriented


  1999-01-21
  1999-01-25
  
   Ashok Malhotra
   123 Microsoft Ave.
   Hawthorne
   NY
   10532-0000
  
  555-1234
  555-4321


  Paul V. Biron
  Ashok Malhotra
  Latest draft
  
    We need to discuss the latest
    draft immediately.
    Either email me at 
    mailto:[email protected]
    or call 555-9876

The invoice contains several dates and telephone numbers, the postal abbreviation for a state (which comes from an enumerated list of sanctioned values), and a ZIP code (which takes a definable regular form). The memo contains many of the same types of information: a date, telephone number, email address and an "importance" value (from an enumerated list, such as "low", "medium" or "high"). Applications which process invoices and memos need to raise exceptions if something that was supposed to be a date or telephone number does not conform to the rules for valid dates or telephone numbers.

In both cases, validity constraints exist on the content of the instances that are not expressible in XML DTDs. The limited datatyping facilities in XML have prevented validating XML processors from supplying the rigorous type checking required in these situations. The result has been that individual applications writers have had to implement type checking in an ad hoc manner. This specification addresses the need of both document authors and applications writers for a robust, extensible datatype system for XML which could be incorporated into XML processors. As discussed below, these datatypes could be used in other XML-related standards as well.

1.2 Requirements

The [XML Schema Requirements] document spells out concrete requirements to be fulfilled by this specification, which state that the XML Schema Language must:

provide for primitive data typing, including byte, date, integer, sequence, SQL and Java primitive datatypes, etc.;
define a type system that is adequate for import/export from database systems (e.g., relational, object, OLAP);
distinguish requirements relating to lexical data representation vs. those governing an underlying information set;
allow creation of user-defined datatypes, such as datatypes that are derived from existing datatypes and which may constrain certain of its properties (e.g., range, precision, length, format).

1.3 Scope

This portion of the XML Schema Language discusses datatypes that can be used in an XML Schema. These datatypes can be specified for element content that would be specified as #PCDATA and attribute values of various types in a DTD. It is the intention of this specification that it be usable outside of the context of XML Schemas for a wide range of other XML-related activities such as [XSL] and [RDF Schema].

1.4 Terminology

The terminology used to describe XML Schema Datatypes is defined in the body of this specification. The terms defined in the following list are used in building those definitions and in describing the actions of a datatype processor:

[Definition:] for compatibility: A feature of this specification included solely to ensure that schemas which use this feature remain compatible with [XML 1.0 (Second Edition)]
[Definition:] may: Conforming documents and processors are permitted to but need not behave as described.
[Definition:] match: (Of strings or names:) Two strings or names being compared must be identical. Characters with multiple possible representations in ISO/IEC 10646 (e.g. characters with both precomposed and base+diacritic forms) match only if they have the same representation in both strings. No case folding is performed. (Of strings and rules in the grammar:) A string matches a grammatical production if it belongs to the language generated by that production.
[Definition:] must: Conforming documents and processors are required to behave as described; otherwise they are in ·error ·.
[Definition:] error: A violation of the rules of this specification; results are undefined. Conforming software ·may · detect and report an error and ·may · recover from it.

1.5 Constraints and Contributions

This specification provides three different kinds of normative statements about schema components, their representations in XML and their contribution to the schema-validation of information items:

[Definition:] Constraint on Schemas: Constraints on the schema components themselves, i.e. conditions components ·must · satisfy to be components at all. Largely to be found in Datatype components (§4).
[Definition:] Schema Representation Constraint: Constraints on the representation of schema components in XML. Some but not all of these are expressed in Schema for Datatype Definitions (normative) (§A) and DTD for Datatype Definitions (non-normative) (§B).
[Definition:] Validation Rule: Constraints expressed by schema components which information items ·must · satisfy to be schema-valid. Largely to be found in Datatype components (§4).

2 Type System

This section describes the conceptual framework behind the type system defined in this specification. The framework has been influenced by the [ISO 11404] standard on language-independent datatypes as well as the datatypes for [SQL] and for programming languages such as Java.

The datatypes discussed in this specification are computer representations of well known abstract concepts such as integer and date. It is not the place of this specification to define these abstract concepts; many other publications provide excellent definitions.

2.1 Datatype

[Definition:] In this specification, a datatype is a 3-tuple, consisting of a) a set of distinct values, called its ·value space·, b) a set of lexical representations, called its ·lexical space·, and c) a set of ·facet·s that characterize properties of the ·value space·, individual values or lexical items.

2.2 Value space

[Definition:] A value space is the set of values for a given datatype. Each value in the value space of a datatype is denoted by one or more literals in its ·lexical space·.

The ·value space· of a given datatype can be defined in one of the following ways:

defined axiomatically from fundamental notions (intensional definition) [see ·primitive·]
enumerated outright (extensional definition) [see ·enumeration·]
defined by restricting the ·value space· of an already defined datatype to a particular subset with a given set of properties [see ·derived·]
defined as a combination of values from one or more already defined ·value space·(s) by a specific construction procedure [see ·list· and ·union·]

·value space·s have certain properties. For example, they always have the property of ·cardinality·, some definition of equality and might be ·ordered·, by which individual values within the ·value space· can be compared to one another. The properties of ·value space·s that are recognized by this specification are defined in Fundamental facets (§2.4.1).

2.3 Lexical space

In addition to its ·value space·, each datatype also has a lexical space.

[Definition:] A lexical space is the set of valid literals for a datatype.

For example, "100" and "1.0E2" are two different literals from the ·lexical space· of float which both denote the same value. The type system defined in this specification provides a mechanism for schema designers to control the set of values and the corresponding set of acceptable literals of those values for a datatype.

Note: The literals in the ·lexical space ·s defined in this specification have the following characteristics:

Interoperability:: The number of literals for each value has been kept small; for many datatypes there is a one-to-one mapping between literals and values. This makes it easy to exchange the values between different systems. In many cases, conversion from locale-dependent representations will be required on both the originator and the recipient side, both for computer processing and for interaction with humans.
Basic readability:: Textual, rather than binary, literals are used. This makes hand editing, debugging, and similar activities possible.
Ease of parsing and serializing:: Where possible, literals correspond to those found in common programming languages and libraries.

2.3.1 Canonical Lexical Representation

While the datatypes defined in this specification have, for the most part, a single lexical representation i.e. each value in the datatype's ·value space· is denoted by a single literal in its ·lexical space·, this is not always the case. The example in the previous section showed two literals for the datatype float which denote the same value. Similarly, there ·may· be several literals for one of the date or time datatypes that denote the same value using different timezone indicators.

[Definition:] A canonical lexical representation is a set of literals from among the valid set of literals for a datatype such that there is a one-to-one mapping between literals in the canonical lexical representation and values in the ·value space·.

2.4 Facets

2.4.1 Fundamental facets
2.4.2 Constraining or Non-fundamental facets

[Definition:] A facet is a single defining aspect of a ·value space·. Generally speaking, each facet characterizes a ·value space· along independent axes or dimensions.

The facets of a datatype serve to distinguish those aspects of one datatype which differ from other datatypes. Rather than being defined solely in terms of a prose description the datatypes in this specification are defined in terms of the synthesis of facet values which together determine the ·value space· and properties of the datatype.

Facets are of two types: fundamental facets that define the datatype and non-fundamental or constraining facets that constrain the permitted values of a datatype.

2.4.1 Fundamental facets

[Definition:] A fundamental facet is an abstract property which serves to semantically characterize the values in a ·value space·.

All fundamental facets are fully described in Fundamental Facets (§4.2).

2.4.2 Constraining or Non-fundamental facets

[Definition:] A constraining facet is an optional property that can be applied to a datatype to constrain its ·value space·.

Constraining the ·value space· consequently constrains the ·lexical space·. Adding ·constraining facet·s to a ·base type· is described in Derivation by restriction (§4.1.2.1).

All constraining facets are fully described in Constraining Facets (§4.3).

2.5 Datatype dichotomies

        2.5.1 Atomic vs. list vs. union datatypes
        2.5.2 Primitive vs. derived datatypes
        2.5.3 Built-in vs. user-derived datatypes

It is useful to categorize the datatypes defined in this specification along various dimensions, forming a set of characterization dichotomies.

2.5.1 Atomic vs. list vs. union datatypes

The first distinction to be made is that between ·atomic·, ·list· and ·union· datatypes.

[Definition:] Atomic datatypes are those having values which are regarded by this specification as being indivisible.
[Definition:] List datatypes are those having values each of which consists of a finite-length (possibly empty) sequence of values of an ·atomic· datatype.
[Definition:] Union datatypes are those whose ·value space·s and ·lexical space·s are the union of the ·value space·s and ·lexical space·s of one or more other datatypes.

For example, a single token which ·match·es Nmtoken from [XML 1.0 (Second Edition)] could be the value of an ·atomic· datatype (NMTOKEN); while a sequence of such tokens could be the value of a ·list· datatype (NMTOKENS).

2.5.1.1 Atomic datatypes

·atomic· datatypes can be either ·primitive· or ·derived·. The ·value space· of an ·atomic· datatype is a set of "atomic" values, which for the purposes of this specification, are not further decomposable. The ·lexical space· of an ·atomic· datatype is a set of literals whose internal structure is specific to the datatype in question.

2.5.1.2 List datatypes

Several type systems (such as the one described in [ISO 11404]) treat ·list· datatypes as special cases of the more general notions of aggregate or collection datatypes.

·list· datatypes are always ·derived·. The ·value space· of a ·list· datatype is a set of finite-length sequences of ·atomic· values. The ·lexical space· of a ·list· datatype is a set of literals whose internal structure is a space-separated sequence of literals of the ·atomic· datatype of the items in the ·list·.

[Definition:] The ·atomic· or ·union· datatype that participates in the definition of a ·list· datatype is known as the itemType of that ·list· datatype.

Example

 8 10.5 12

A ·list· datatype can be ·derived· from an ·atomic· datatype whose ·lexical space· allows space (such as string or anyURI)or a ·union· datatype any of whose {member type definitions}'s ·lexical space· allows space. In such a case, regardless of the input, list items will be separated at space boundaries.

Example


this is not list item 1
this is not list item 2
this is not list item 3

In the above example, the value of the someElement element is not a ·list · of ·length · 3; rather, it is a ·list · of ·length · 18.

When a datatype is ·derived· from a ·list· datatype, the following ·constraining facet·s apply:

·length·
·maxLength·
·minLength·
·enumeration·
·pattern·
·whiteSpace·

For each of ·length·, ·maxLength· and ·minLength·, the unit of length is measured in number of list items. The value of ·whiteSpace· is fixed to the value collapse.

For ·list· datatypes the ·lexical space· is composed of space-separated literals of its ·itemType·. Hence, any ·pattern· specified when a new datatype is ·derived· from a ·list· datatype is matched against each literal of the ·list· datatype and not against the literals of the datatype that serves as its ·itemType·.

Example


	


	
		
	

123 456
123 987 456
123 987 567 456

The canonical-lexical-representation for the ·list· datatype is defined as the lexical form in which each item in the ·list· has the canonical lexical representation of its ·itemType·.

2.5.1.3 Union datatypes

The ·value space· and ·lexical space· of a ·union· datatype are the union of the ·value space·s and ·lexical space·s of its ·memberTypes·. ·union· datatypes are always ·derived·. Currently, there are no ·built-in· ·union· datatypes.

Example

A prototypical example of a ·union · type is the maxOccurs attribute on the element element in XML Schema itself: it is a union of nonNegativeInteger and an enumeration with the single member, the string "unbounded", as shown below.

Any number (greater than 1) of ·atomic· or ·list· ·datatype·s can participate in a ·union· type.

[Definition:] The datatypes that participate in the definition of a ·union· datatype are known as the memberTypes of that ·union· datatype.

The order in which the ·memberTypes· are specified in the definition (that is, the order of the children of the element, or the order of the QNames in the memberTypes attribute) is significant. During validation, an element or attribute's value is validated against the ·memberTypes· in the order in which they appear in the definition until a match is found. The evaluation order can be overridden with the use of xsi:type.

Example

For example, given the definition below, the first instance of the element validates correctly as an integer (§3.3.13), the second and third as string (§3.2.1).

  1
  large
  1

The canonical-lexical-representation for a ·union· datatype is defined as the lexical form in which the values have the canonical lexical representation of the appropriate ·memberTypes·.

Note: A datatype which is ·atomic · in this specification need not be an "atomic" datatype in any programming language used to implement this specification. Likewise, a datatype which is a ·list · in this specification need not be a "list" datatype in any programming language used to implement this specification. Furthermore, a datatype which is a ·union · in this specification need not be a "union" datatype in any programming language used to implement this specification.

2.5.2 Primitive vs. derived datatypes

Next, we distinguish between ·primitive· and ·derived· datatypes.

[Definition:] Primitive datatypes are those that are not defined in terms of other datatypes; they exist ab initio.
[Definition:] Derived datatypes are those that are defined in terms of other datatypes.

For example, in this specification, float is a well-defined mathematical concept that cannot be defined in terms of other datatypes, while a integer is a special case of the more general datatype decimal.

[Definition:] The simple ur-type definition is a special restriction of the ur-type definition whose name is anySimpleType in the XML Schema namespace. anySimpleType can be considered as the ·base type· of all ·primitive· datatypes. anySimpleType is considered to have an unconstrained lexical space and a ·value space· consisting of the union of the ·value space·s of all the ·primitive· datatypes and the set of all lists of all members of the ·value space·s of all the ·primitive· datatypes.

The datatypes defined by this specification fall into both the ·primitive· and ·derived· categories. It is felt that a judiciously chosen set of ·primitive· datatypes will serve the widest possible audience by providing a set of convenient datatypes that can be used as is, as well as providing a rich enough base from which the variety of datatypes needed by schema designers can be ·derived·.

In the example above, integer is ·derived· from decimal.

Note: A datatype which is ·primitive · in this specification need not be a "primitive" datatype in any programming language used to implement this specification. Likewise, a datatype which is ·derived · in this specification need not be a "derived" datatype in any programming language used to implement this specification.

As described in more detail in XML Representation of Simple Type Definition Schema Components (§4.1.2), each ·user-derived· datatype ·must· be defined in terms of another datatype in one of three ways: 1) by assigning ·constraining facet·s which serve to restrict the ·value space· of the ·user-derived· datatype to a subset of that of the ·base type·; 2) by creating a ·list· datatype whose ·value space· consists of finite-length sequences of values of its ·itemType·; or 3) by creating a ·union· datatype whose ·value space· consists of the union of the ·value space·s of its ·memberTypes·.

2.5.2.1 Derived by restriction

[Definition:] A datatype is said to be ·derived· by restriction from another datatype when values for zero or more ·constraining facet·s are specified that serve to constrain its ·value space· and/or its ·lexical space· to a subset of those of its ·base type·.

[Definition:] Every datatype that is ·derived· by restriction is defined in terms of an existing datatype, referred to as its base type. base types can be either ·primitive· or ·derived·.

2.5.2.2 Derived by list

A ·list· datatype can be ·derived· from another datatype (its ·itemType·) by creating a ·value space· that consists of a finite-length sequence of values of its ·itemType·.

2.5.2.3 Derived by union

One datatype can be ·derived· from one or more datatypes by ·union·ing their ·value space·s and, consequently, their ·lexical space·s.

2.5.3 Built-in vs. user-derived datatypes

[Definition:] Built-in datatypes are those which are defined in this specification, and can be either ·primitive· or ·derived·;
[Definition:] User-derived datatypes are those ·derived· datatypes that are defined by individual schema designers.

Conceptually there is no difference between the ·built-in· ·derived· datatypes included in this specification and the ·user-derived· datatypes which will be created by individual schema designers. The ·built-in· ·derived· datatypes are those which are believed to be so common that if they were not defined in this specification many schema designers would end up "reinventing" them. Furthermore, including these ·derived· datatypes in this specification serves to demonstrate the mechanics and utility of the datatype generation facilities of this specification.

Note: A datatype which is ·built-in · in this specification need not be a "built-in" datatype in any programming language used to implement this specification. Likewise, a datatype which is ·user-derived · in this specification need not be a "user-derived" datatype in any programming language used to implement this specification.

3 Built-in datatypes

Each built-in datatype in this specification (both ·primitive· and ·derived·) can be uniquely addressed via a URI Reference constructed as follows:

the base URI is the URI of the XML Schema namespace
the fragment identifier is the name of the datatype

For example, to address the int datatype, the URI is:

http://www.w3.org/2001/XMLSchema#int

Additionally, each facet definition element can be uniquely addressed via a URI constructed as follows:

the base URI is the URI of the XML Schema namespace
the fragment identifier is the name of the facet

For example, to address the maxInclusive facet, the URI is:

http://www.w3.org/2001/XMLSchema#maxInclusive

Additionally, each facet usage in a built-in datatype definition can be uniquely addressed via a URI constructed as follows:

the base URI is the URI of the XML Schema namespace
the fragment identifier is the name of the datatype, followed by a period (".") followed by the name of the facet

For example, to address the usage of the maxInclusive facet in the definition of int, the URI is:

http://www.w3.org/2001/XMLSchema#int.maxInclusive

3.1 Namespace considerations

The ·built-in· datatypes defined by this specification are designed to be used with the XML Schema definition language as well as other XML specifications. To facilitate usage within the XML Schema definition language, the ·built-in· datatypes in this specification have the namespace name:

http://www.w3.org/2001/XMLSchema

To facilitate usage in specifications other than the XML Schema definition language, such as those that do not want to know anything about aspects of the XML Schema definition language other than the datatypes, each ·built-in· datatype is also defined in the namespace whose URI is:

http://www.w3.org/2001/XMLSchema-datatypes

This applies to both ·built-in· ·primitive· and ·built-in· ·derived· datatypes.

Each ·user-derived· datatype is also associated with a unique namespace. However, ·user-derived· datatypes do not come from the namespace defined by this specification; rather, they come from the namespace of the schema in which they are defined (see XML Representation of Schemas in [XML Schema Part 1: Structures]).

3.2 Primitive datatypes

        3.2.1 string
        3.2.2 boolean
        3.2.3 decimal
        3.2.4 float
        3.2.5 double
        3.2.6 duration
        3.2.7 dateTime
        3.2.8 time
        3.2.9 date
        3.2.10 gYearMonth
        3.2.11 gYear
        3.2.12 gMonthDay
        3.2.13 gDay
        3.2.14 gMonth
        3.2.15 hexBinary
        3.2.16 base64Binary
        3.2.17 anyURI
        3.2.18 QName
        3.2.19 NOTATION

The ·primitive· datatypes defined by this specification are described below. For each datatype, the ·value space· and ·lexical space· are defined, ·constraining facet·s which apply to the datatype are listed and any datatypes ·derived· from this datatype are specified.

·primitive· datatypes can only be added by revisions to this specification.

3.2.1 string

[Definition:] The string datatype represents character strings in XML. The ·value space· of string is the set of finite-length sequences of characters (as defined in [XML 1.0 (Second Edition)]) that ·match· the Char production from [XML 1.0 (Second Edition)]. A character is an atomic unit of communication; it is not further specified except to note that every character has a corresponding Universal Character Set code point, which is an integer.

Note: Many human languages have writing systems that require child elements for control of aspects such as bidirectional formating or ruby annotation (see [Ruby] and Section 8.2.4 Overriding the bidirectional algorithm: the BDO element of [HTML 4.01]). Thus, string, as a simple type that can contain only characters but not child elements, is often not suitable for representing text. In such situations, a complex type that allows mixed content should be considered. For more information, see Section 5.5 Any Element, Any Attribute of [XML Schema Language: Part 0 Primer].

Note: As noted in ordered, the fact that this specification does not specify an ·order-relation · for ·string · does not preclude other applications from treating strings as being ordered.

3.2.1.1 Constraining facets

string has the following ·constraining facets·:

length
minLength
maxLength
pattern
enumeration
whiteSpace

3.2.1.2 Derived datatypes

The following ·built-in· datatypes are ·derived· from string:

normalizedString

3.2.2 boolean

[Definition:] boolean has the ·value space· required to support the mathematical concept of binary-valued logic: {true, false}.

3.2.2.1 Lexical representation

An instance of a datatype that is defined as ·boolean· can have the following legal literals {true, false, 1, 0}.

3.2.2.2 Canonical representation

The canonical representation for boolean is the set of literals {true, false}.

3.2.2.3 Constraining facets

boolean has the following ·constraining facets·:

pattern
whiteSpace

3.2.3 decimal

[Definition:] decimal represents a subset of the real numbers, which can be represented by decimal numerals. The ·value space· of decimal is the set of numbers that can be obtained by multiplying an integer by a non-positive power of ten, i.e., expressible as i × 10^-n where i and n are integers and n >= 0. Precision is not reflected in this value space; the number 2.0 is not distinct from the number 2.00. The ·order-relation· on decimal is the order relation on real numbers, restricted to this subset.

Note: All ·minimally conforming · processors ·must · support decimal numbers with a minimum of 18 decimal digits (i.e., with a ·totalDigits · of 18). However, ·minimally conforming · processors ·may · set an application-defined limit on the maximum number of decimal digits they are prepared to support, in which case that application-defined maximum number ·must · be clearly documented.

3.2.3.1 Lexical representation

decimal has a lexical representation consisting of a finite-length sequence of decimal digits (#x30-#x39) separated by a period as a decimal indicator. An optional leading sign is allowed. If the sign is omitted, "+" is assumed. Leading and trailing zeroes are optional. If the fractional part is zero, the period and following zero(es) can be omitted. For example: -1.23, 12678967.543233, +100000.00, 210.

3.2.3.2 Canonical representation

The canonical representation for decimal is defined by prohibiting certain options from the Lexical representation (§3.2.3.1). Specifically, the preceding optional "+" sign is prohibited. The decimal point is required. Leading and trailing zeroes are prohibited subject to the following: there must be at least one digit to the right and to the left of the decimal point which may be a zero.

3.2.3.3 Constraining facets

decimal has the following ·constraining facets·:

totalDigits
fractionDigits
pattern
whiteSpace
enumeration
maxInclusive
maxExclusive
minInclusive
minExclusive

3.2.3.4 Derived datatypes

The following ·built-in· datatypes are ·derived· from decimal:

integer

3.2.4 float

[Definition:] float is patterned after the IEEE single-precision 32-bit floating point type [IEEE 754-1985]. The basic ·value space· of float consists of the values m × 2^e, where m is an integer whose absolute value is less than 2^24, and e is an integer between -149 and 104, inclusive. In addition to the basic ·value space· described above, the ·value space· of float also contains the following three special values: positive and negative infinity and not-a-number (NaN). The ·order-relation· on float is: x < y iff y - x is positive for x and y in the value space. Positive infinity is greater than all other non-NaN values. NaN equals itself but is ·incomparable· with (neither greater than nor less than) any other value in the ·value space·.

Note: "Equality" in this Recommendation is defined to be "identity" (i.e., values that are identical in the ·value space · are equal and vice versa). Identity must be used for the few operations that are defined in this Recommendation. Applications using any of the datatypes defined in this Recommendation may use different definitions of equality for computational purposes; [IEEE 754-1985]-based computation systems are examples. Nothing in this Recommendation should be construed as requiring that such applications use identity as their equality relationship when computing.

Any value ·incomparable· with the value used for the four bounding facets (·minInclusive·, ·maxInclusive·, ·minExclusive·, and ·maxExclusive·) will be excluded from the resulting restricted ·value space·. In particular, when "NaN" is used as a facet value for a bounding facet, since no other float values are ·comparable· with it, the result is a ·value space· either having NaN as its only member (the inclusive cases) or that is empty (the exclusive cases). If any other value is used for a bounding facet, NaN will be excluded from the resulting restricted ·value space·; to add NaN back in requires union with the NaN-only space.

This datatype differs from that of [IEEE 754-1985] in that there is only one NaN and only one zero. This makes the equality and ordering of values in the data space differ from that of [IEEE 754-1985] only in that for schema purposes NaN = NaN.

A literal in the ·lexical space· representing a decimal number d maps to the normalized value in the ·value space· of float that is closest to d in the sense defined by [Clinger, WD (1990)]; if d is exactly halfway between two such values then the even value is chosen.

3.2.4.1 Lexical representation

float values have a lexical representation consisting of a mantissa followed, optionally, by the character "E" or "e", followed by an exponent. The exponent ·must· be an integer. The mantissa must be a decimal number. The representations for exponent and mantissa must follow the lexical rules for integer and decimal. If the "E" or "e" and the following exponent are omitted, an exponent value of 0 is assumed.

The special values positive and negative infinity and not-a-number have lexical representations INF, -INF and NaN, respectively. Lexical representations for zero may take a positive or negative sign.

For example, -1E4, 1267.43233E12, 12.78e-2, 12 , -0, 0 and INF are all legal literals for float.

3.2.4.2 Canonical representation

The canonical representation for float is defined by prohibiting certain options from the Lexical representation (§3.2.4.1). Specifically, the exponent must be indicated by "E". Leading zeroes and the preceding optional "+" sign are prohibited in the exponent. If the exponent is zero, it must be indicated by "E0". For the mantissa, the preceding optional "+" sign is prohibited and the decimal point is required. Leading and trailing zeroes are prohibited subject to the following: number representations must be normalized such that there is a single digit which is non-zero to the left of the decimal point and at least a single digit to the right of the decimal point unless the value being represented is zero. The canonical representation for zero is 0.0E0.

3.2.4.3 Constraining facets

float has the following ·constraining facets·:

pattern
enumeration
whiteSpace
maxInclusive
maxExclusive
minInclusive
minExclusive

3.2.5 double

[Definition:] The double datatype is patterned after the IEEE double-precision 64-bit floating point type [IEEE 754-1985]. The basic ·value space· of double consists of the values m × 2^e, where m is an integer whose absolute value is less than 2^53, and e is an integer between -1075 and 970, inclusive. In addition to the basic ·value space· described above, the ·value space· of double also contains the following three special values: positive and negative infinity and not-a-number (NaN). The ·order-relation· on double is: x < y iff y - x is positive for x and y in the value space. Positive infinity is greater than all other non-NaN values. NaN equals itself but is ·incomparable· with (neither greater than nor less than) any other value in the ·value space·.

Any value ·incomparable· with the value used for the four bounding facets (·minInclusive·, ·maxInclusive·, ·minExclusive·, and ·maxExclusive·) will be excluded from the resulting restricted ·value space·. In particular, when "NaN" is used as a facet value for a bounding facet, since no other double values are ·comparable· with it, the result is a ·value space· either having NaN as its only member (the inclusive cases) or that is empty (the exclusive cases). If any other value is used for a bounding facet, NaN will be excluded from the resulting restricted ·value space·; to add NaN back in requires union with the NaN-only space.

A literal in the ·lexical space· representing a decimal number d maps to the normalized value in the ·value space· of double that is closest to d; if d is exactly halfway between two such values then the even value is chosen. This is the best approximation of d ([Clinger, WD (1990)], [Gay, DM (1990)]), which is more accurate than the mapping required by [IEEE 754-1985].

3.2.5.1 Lexical representation

double values have a lexical representation consisting of a mantissa followed, optionally, by the character "E" or "e", followed by an exponent. The exponent ·must· be an integer. The mantissa must be a decimal number. The representations for exponent and mantissa must follow the lexical rules for integer and decimal. If the "E" or "e" and the following exponent are omitted, an exponent value of 0 is assumed.

For example, -1E4, 1267.43233E12, 12.78e-2, 12 , -0, 0 and INF are all legal literals for double.

3.2.5.2 Canonical representation

The canonical representation for double is defined by prohibiting certain options from the Lexical representation (§3.2.5.1). Specifically, the exponent must be indicated by "E". Leading zeroes and the preceding optional "+" sign are prohibited in the exponent. If the exponent is zero, it must be indicated by "E0". For the mantissa, the preceding optional "+" sign is prohibited and the decimal point is required. Leading and trailing zeroes are prohibited subject to the following: number representations must be normalized such that there is a single digit which is non-zero to the left of the decimal point and at least a single digit to the right of the decimal point unless the value being represented is zero. The canonical representation for zero is 0.0E0.

3.2.5.3 Constraining facets

double has the following ·constraining facets·:

pattern
enumeration
whiteSpace
maxInclusive
maxExclusive
minInclusive
minExclusive

3.2.6 duration

[Definition:] duration represents a duration of time. The ·value space· of duration is a six-dimensional space where the coordinates designate the Gregorian year, month, day, hour, minute, and second components defined in § 5.5.3.2 of [ISO 8601], respectively. These components are ordered in their significance by their order of appearance i.e. as year, month, day, hour, minute, and second.

Note:

All ·minimally conforming · processors ·must · support year values with a minimum of 4 digits (i.e., YYYY) and a minimum fractional second precision of milliseconds or three decimal digits (i.e. s.sss). However, ·minimally conforming · processors ·may · set an application-defined limit on the maximum number of digits they are prepared to support in these two cases, in which case that application-defined maximum number ·must · be clearly documented.

3.2.6.1 Lexical representation

The lexical representation for duration is the [ISO 8601] extended format PnYn MnDTnH nMnS, where nY represents the number of years, nM the number of months, nD the number of days, 'T' is the date/time separator, nH the number of hours, nM the number of minutes and nS the number of seconds. The number of seconds can include decimal digits to arbitrary precision.

The values of the Year, Month, Day, Hour and Minutes components are not restricted but allow an arbitrary unsigned integer, i.e., an integer that conforms to the pattern [0-9]+.. Similarly, the value of the Seconds component allows an arbitrary unsigned decimal. Following [ISO 8601], at least one digit must follow the decimal point if it appears. That is, the value of the Seconds component must conform to the pattern [0-9]+(/.[0-9]+)?. Thus, the lexical representation of duration does not follow the alternative format of § 5.5.3.2.1 of [ISO 8601].

An optional preceding minus sign ('-') is allowed, to indicate a negative duration. If the sign is omitted a positive duration is indicated. See also ISO 8601 Date and Time Formats (§D).

For example, to indicate a duration of 1 year, 2 months, 3 days, 10 hours, and 30 minutes, one would write: P1Y2M3DT10H30M. One could also indicate a duration of minus 120 days as: -P120D.

Reduced precision and truncated representations of this format are allowed provided they conform to the following:

If the number of years, months, days, hours, minutes, or seconds in any expression equals zero, the number and its corresponding designator ·may· be omitted. However, at least one number and its designator ·must· be present.
The seconds part ·may· have a decimal fraction.
The designator 'T' must be absent if and only if all of the time items are absent. The designator 'P' must always be present.

For example, P1347Y, P1347M and P1Y2MT2H are all allowed; P0Y1347M and P0Y1347M0D are allowed. P-1347M is not allowed although -P1347M is allowed. P1Y2MT is not allowed.

3.2.6.2 Order relation on duration

In general, the ·order-relation· on duration is a partial order since there is no determinate relationship between certain durations such as one month (P1M) and 30 days (P30D). The ·order-relation· of two duration values x and y is x < y iff s+x < s+y for each qualified dateTime s in the list below. These values for s cause the greatest deviations in the addition of dateTimes and durations. Addition of durations to time instants is defined in Adding durations to dateTimes (§E).

1696-09-01T00:00:00Z
1697-02-01T00:00:00Z
1903-03-01T00:00:00Z
1903-07-01T00:00:00Z

The following table shows the strongest relationship that can be determined between example durations. The symbol <> means that the order relation is indeterminate. Note that because of leap-seconds, a seconds field can vary from 59 to 60. However, because of the way that addition is defined in Adding durations to dateTimes (§E), they are still totally ordered.

	Relation
P1Y	> P364D	<> P365D				<> P366D	< P367D
P1M	> P27D	<> P28D	<> P29D		<> P30D	<> P31D	< P32D
P5M	> P149D	<> P150D	<> P151D	<> P152D		<> P153D	< P154D

Implementations are free to optimize the computation of the ordering relationship. For example, the following table can be used to compare durations of a small number of months against days.

	Months	1	2	3	4	5	6	7	8	9	10	11	12	13	...
Days	Minimum	28	59	89	120	150	181	212	242	273	303	334	365	393	...
Days	Maximum	31	62	92	123	153	184	215	245	276	306	337	366	397	...

3.2.6.3 Facet Comparison for durations

In comparing duration values with minInclusive, minExclusive, maxInclusive and maxExclusive facet values indeterminate comparisons should be considered as "false".

3.2.6.4 Totally ordered durations

Certain derived datatypes of durations can be guaranteed have a total order. For this, they must have fields from only one row in the list below and the time zone must either be required or prohibited.

year, month
day, hour, minute, second

For example, a datatype could be defined to correspond to the [SQL] datatype Year-Month interval that required a four digit year field and a two digit month field but required all other fields to be unspecified. This datatype could be defined as below and would have a total order.

3.2.6.5 Constraining facets

duration has the following ·constraining facets·:

pattern
enumeration
whiteSpace
maxInclusive
maxExclusive
minInclusive
minExclusive

3.2.7 dateTime

[Definition:] dateTime values may be viewed as objects with integer-valued year, month, day, hour and minute properties, a decimal-valued second property, and a boolean timezoned property. Each such object also has one decimal-valued method or computed property, timeOnTimeline, whose value is always a decimal number; the values are dimensioned in seconds, the integer 0 is 0001-01-01T00:00:00 and the value of timeOnTimeline for other dateTime values is computed using the Gregorian algorithm as modified for leap-seconds. The timeOnTimeline values form two related "timelines", one for timezoned values and one for non-timezoned values. Each timeline is a copy of the ·value space· of decimal, with integers given units of seconds.

The ·value space· of dateTime is closely related to the dates and times described in ISO 8601. For clarity, the text above specifies a particular origin point for the timeline. It should be noted, however, that schema processors need not expose the timeOnTimeline value to schema users, and there is no requirement that a timeline-based implementation use the particular origin described here in its internal representation. Other interpretations of the ·value space· which lead to the same results (i.e., are isomorphic) are of course acceptable.

All timezoned times are Coordinated Universal Time (UTC, sometimes called "Greenwich Mean Time"). Other timezones indicated in lexical representations are converted to UTC during conversion of literals to values. "Local" or untimezoned times are presumed to be the time in the timezone of some unspecified locality as prescribed by the appropriate legal authority; currently there are no legally prescribed timezones which are durations whose magnitude is greater than 14 hours. The value of each numeric-valued property (other than timeOnTimeline) is limited to the maximum value within the interval determined by the next-higher property. For example, the day value can never be 32, and cannot even be 29 for month 02 and year 2002 (February 2002).

Note:

The date and time datatypes described in this recommendation were inspired by [ISO 8601]. '0001' is the lexical representation of the year 1 of the Common Era (1 CE, sometimes written "AD 1" or "1 AD"). There is no year 0, and '0000' is not a valid lexical representation. '-0001' is the lexical representation of the year 1 Before Common Era (1 BCE, sometimes written "1 BC").

Those using this (1.0) version of this Recommendation to represent negative years should be aware that the interpretation of lexical representations beginning with a '-' is likely to change in subsequent versions.

[ISO 8601] makes no mention of the year 0; in [ISO 8601:1998 Draft Revision] the form '0000' was disallowed and this recommendation disallows it as well. However, [ISO 8601:2000 Second Edition], which became available just as we were completing version 1.0, allows the form '0000', representing the year 1 BCE. A number of external commentators have also suggested that '0000' be allowed, as the lexical representation for 1 BCE, which is the normal usage in astronomical contexts. It is the intention of the XML Schema Working Group to allow '0000' as a lexical representation in the dateTime, date, gYear, and gYearMonth datatypes in a subsequent version of this Recommendation. '0000' will be the lexical representation of 1 BCE (which is a leap year), '-0001' will become the lexical representation of 2 BCE (not 1 BCE as in this (1.0) version), '-0002' of 3 BCE, etc.

Note: See the conformance note in (§3.2.6) which applies to this datatype as well.

3.2.7.1 Lexical representation

The ·lexical space· of dateTime consists of finite-length sequences of characters of the form: '-'? yyyy '-' mm '-' dd 'T' hh ':' mm ':' ss ('.' s+)? (zzzzzz)?, where

'-'? yyyy is a four-or-more digit optionally negative-signed numeral that represents the year; if more than four digits, leading zeros are prohibited, and '0000' is prohibited (see the Note above (§3.2.7); also note that a plus sign is not permitted);
the remaining '-'s are separators between parts of the date portion;
the first mm is a two-digit numeral that represents the month;
dd is a two-digit numeral that represents the day;
'T' is a separator indicating that time-of-day follows;
hh is a two-digit numeral that represents the hour; '24' is permitted if the minutes and seconds represented are zero, and the dateTime value so represented is the first instant of the following day (the hour property of a dateTime object in the ·value space· cannot have a value greater than 23);
':' is a separator between parts of the time-of-day portion;
the second mm is a two-digit numeral that represents the minute;
ss is a two-integer-digit numeral that represents the whole seconds;
'.' s+ (if present) represents the fractional seconds;
zzzzzz (if present) represents the timezone (as described below).

For example, 2002-10-10T12:00:00-05:00 (noon on 10 October 2002, Central Daylight Savings Time as well as Eastern Standard Time in the U.S.) is 2002-10-10T17:00:00Z, five hours later than 2002-10-10T12:00:00Z.

For further guidance on arithmetic with dateTimes and durations, see Adding durations to dateTimes (§E).

3.2.7.2 Canonical representation

Except for trailing fractional zero digits in the seconds representation, '24:00:00' time representations, and timezone (for timezoned values), the mapping from literals to values is one-to-one. Where there is more than one possible representation, the canonical representation is as follows:

The 2-digit numeral representing the hour must not be '24';
The fractional second string, if present, must not end in '0';
for timezoned values, the timezone must be represented with 'Z' (All timezoned dateTime values are UTC.).

3.2.7.3 Timezones

Timezones are durations with (integer-valued) hour and minute properties (with the hour magnitude limited to at most 14, and the minute magnitude limited to at most 59, except that if the hour magnitude is 14, the minute value must be 0); they may be both positive or both negative.

The lexical representation of a timezone is a string of the form: (('+' | '-') hh ':' mm) | 'Z', where

hh is a two-digit numeral (with leading zeros as required) that represents the hours,
mm is a two-digit numeral that represents the minutes,
'+' indicates a nonnegative duration,
'-' indicates a nonpositive duration.

The mapping so defined is one-to-one, except that '+00:00', '-00:00', and 'Z' all represent the same zero-length duration timezone, UTC; 'Z' is its canonical representation.

When a timezone is added to a UTC dateTime, the result is the date and time "in that timezone". For example, 2002-10-10T12:00:00+05:00 is 2002-10-10T07:00:00Z and 2002-10-10T00:00:00+05:00 is 2002-10-09T19:00:00Z.

3.2.7.4 Order relation on dateTime

dateTime value objects on either timeline are totally ordered by their timeOnTimeline values; between the two timelines, dateTime value objects are ordered by their timeOnTimeline values when their timeOnTimeline values differ by more than fourteen hours, with those whose difference is a duration of 14 hours or less being ·incomparable·.

In general, the ·order-relation· on dateTime is a partial order since there is no determinate relationship between certain instants. For example, there is no determinate ordering between (a) 2000-01-20T12:00:00 and (b) 2000-01-20T12:00:00Z. Based on timezones currently in use, (c) could vary from 2000-01-20T12:00:00+12:00 to 2000-01-20T12:00:00-13:00. It is, however, possible for this range to expand or contract in the future, based on local laws. Because of this, the following definition uses a somewhat broader range of indeterminate values: +14:00..-14:00.

The following definition uses the notation S[year] to represent the year field of S, S[month] to represent the month field, and so on. The notation (Q & "-14:00") means adding the timezone -14:00 to Q, where Q did not already have a timezone. This is a logical explanation of the process. Actual implementations are free to optimize as long as they produce the same results.

The ordering between two dateTimes P and Q is defined by the following algorithm:

A.Normalize P and Q. That is, if there is a timezone present, but it is not Z, convert it to Z using the addition operation defined in Adding durations to dateTimes (§E)

Thus 2000-03-04T23:00:00+03:00 normalizes to 2000-03-04T20:00:00Z

B. If P and Q either both have a time zone or both do not have a time zone, compare P and Q field by field from the year field down to the second field, and return a result as soon as it can be determined. That is:

For each i in {year, month, day, hour, minute, second}
1. If P[i] and Q[i] are both not specified, continue to the next i
2. If P[i] is not specified and Q[i] is, or vice versa, stop and return P <> Q
3. If P[i] < Q[i], stop and return P < Q
4. If P[i] > Q[i], stop and return P > Q
Stop and return P = Q

C.Otherwise, if P contains a time zone and Q does not, compare as follows:

P < Q if P < (Q with time zone +14:00)
P > Q if P > (Q with time zone -14:00)
P <> Q otherwise, that is, if (Q with time zone +14:00) < P < (Q with time zone -14:00)

D. Otherwise, if P does not contain a time zone and Q does, compare as follows:

P < Q if (P with time zone -14:00) < Q.
P > Q if (P with time zone +14:00) > Q.
P <> Q otherwise, that is, if (P with time zone +14:00) < Q < (P with time zone -14:00)

Examples:

Determinate	Indeterminate
2000-01-15T00:00:00 < 2000-02-15T00:00:00	2000-01-01T12:00:00 <> 1999-12-31T23:00:00Z
2000-01-15T12:00:00 < 2000-01-16T12:00:00Z	2000-01-16T12:00:00 <> 2000-01-16T12:00:00Z
	2000-01-16T00:00:00 <> 2000-01-16T12:00:00Z

3.2.7.5 Totally ordered dateTimes

Certain derived types from dateTime can be guaranteed have a total order. To do so, they must require that a specific set of fields are always specified, and that remaining fields (if any) are always unspecified. For example, the date datatype without time zone is defined to contain exactly year, month, and day. Thus dates without time zone have a total order among themselves.

3.2.7.6 Constraining facets

dateTime has the following ·constraining facets·:

pattern
enumeration
whiteSpace
maxInclusive
maxExclusive
minInclusive
minExclusive

3.2.8 time

[Definition:] time represents an instant of time that recurs every day. The ·value space· of time is the space of time of day values as defined in § 5.3 of [ISO 8601]. Specifically, it is a set of zero-duration daily time instances.

Since the lexical representation allows an optional time zone indicator, time values are partially ordered because it may not be able to determine the order of two values one of which has a time zone and the other does not. The order relation on time values is the Order relation on dateTime (§3.2.7.4) using an arbitrary date. See also Adding durations to dateTimes (§E). Pairs of time values with or without time zone indicators are totally ordered.

Note: See the conformance note in (§3.2.6) which applies to the seconds part of this datatype as well.

3.2.8.1 Lexical representation

The lexical representation for time is the left truncated lexical representation for dateTime: hh:mm:ss.sss with optional following time zone indicator. For example, to indicate 1:20 pm for Eastern Standard Time which is 5 hours behind Coordinated Universal Time (UTC), one would write: 13:20:00-05:00. See also ISO 8601 Date and Time Formats (§D).

3.2.8.2 Canonical representation

The canonical representation for time is defined by prohibiting certain options from the Lexical representation (§3.2.8.1). Specifically, either the time zone must be omitted or, if present, the time zone must be Coordinated Universal Time (UTC) indicated by a "Z". Additionally, the canonical representation for midnight is 00:00:00.

3.2.8.3 Constraining facets

time has the following ·constraining facets·:

pattern
enumeration
whiteSpace
maxInclusive
maxExclusive
minInclusive
minExclusive

3.2.9 date

[Definition:] The ·value space· of date consists of top-open intervals of exactly one day in length on the timelines of dateTime, beginning on the beginning moment of each day (in each timezone), i.e. '00:00:00', up to but not including '24:00:00' (which is identical with '00:00:00' of the next day). For nontimezoned values, the top-open intervals disjointly cover the nontimezoned timeline, one per day. For timezoned values, the intervals begin at every minute and therefore overlap.

A "date object" is an object with year, month, and day properties just like those of dateTime objects, plus an optional timezone-valued timezone property. (As with values of dateTime timezones are a special case of durations.) Just as a dateTime object corresponds to a point on one of the timelines, a date object corresponds to an interval on one of the two timelines as just described.

Timezoned date values track the starting moment of their day, as determined by their timezone; said timezone is generally recoverable for canonical representations. [Definition:] The recoverable timezone is that duration which is the result of subtracting the first moment (or any moment) of the timezoned date from the first moment (or the corresponding moment) UTC on the same date. ·recoverable timezone·s are always durations between '+12:00' and '-11:59'. This "timezone normalization" (which follows automatically from the definition of the date ·value space·) is explained more in Lexical representation (§3.2.9.1).

For example: the first moment of 2002-10-10+13:00 is 2002-10-10T00:00:00+13, which is 2002-10-09T11:00:00Z, which is also the first moment of 2002-10-09-11:00. Therefore 2002-10-10+13:00 is 2002-10-09-11:00; they are the same interval.

Note: For most timezones, either the first moment or last moment of the day (a dateTime value, always UTC) will have a date portion different from that of the date itself! However, noon of that date (the midpoint of the interval) in that (normalized) timezone will always have the same date portion as the date itself, even when that noon point in time is normalized to UTC. For example, 2002-10-10-05:00 begins during 2002-10-09Z and 2002-10-10+05:00 ends during 2002-10-11Z, but noon of both 2002-10-10-05:00 and 2002-10-10+05:00 falls in the interval which is 2002-10-10Z.

Note: See the conformance note in (§3.2.6) which applies to the year part of this datatype as well.

3.2.9.1 Lexical representation

For the following discussion, let the "date portion" of a dateTime or date object be an object similar to a dateTime or date object, with similar year, month, and day properties, but no others, having the same value for these properties as the original dateTime or date object.

The ·lexical space· of date consists of finite-length sequences of characters of the form: '-'? yyyy '-' mm '-' dd zzzzzz? where the date and optional timezone are represented exactly the same way as they are for dateTime. The first moment of the interval is that represented by: '-' yyyy '-' mm '-' dd 'T00:00:00' zzzzzz? and the least upper bound of the interval is the timeline point represented (noncanonically) by: '-' yyyy '-' mm '-' dd 'T24:00:00' zzzzzz?.

Note: The ·recoverable timezone · of a date will always be a duration between '+12:00' and '11:59'. Timezone lexical representations, as explained for dateTime, can range from '+14:00' to '-14:00'. The result is that literals of dates with very large or very negative timezones will map to a "normalized" date value with a ·recoverable timezone · different from that represented in the original representation, and a matching difference of +/- 1 day in the date itself.

3.2.9.2 Canonical representation

Given a member of the date ·value space·, the date portion of the canonical representation (the entire representation for nontimezoned values, and all but the timezone representation for timezoned values) is always the date portion of the dateTime canonical representation of the interval midpoint (the dateTime representation, truncated on the right to eliminate 'T' and all following characters). For timezoned values, append the canonical representation of the ·recoverable timezone·.

3.2.10 gYearMonth

[Definition:] gYearMonth represents a specific gregorian month in a specific gregorian year. The ·value space· of gYearMonth is the set of Gregorian calendar months as defined in § 5.2.1 of [ISO 8601]. Specifically, it is a set of one-month long, non-periodic instances e.g. 1999-10 to represent the whole month of 1999-10, independent of how many days this month has.

Since the lexical representation allows an optional time zone indicator, gYearMonth values are partially ordered because it may not be possible to unequivocally determine the order of two values one of which has a time zone and the other does not. If gYearMonth values are considered as periods of time, the order relation on gYearMonth values is the order relation on their starting instants. This is discussed in Order relation on dateTime (§3.2.7.4). See also Adding durations to dateTimes (§E). Pairs of gYearMonth values with or without time zone indicators are totally ordered.

Note: Because month/year combinations in one calendar only rarely correspond to month/year combinations in other calendars, values of this type are not, in general, convertible to simple values corresponding to month/year combinations in other calendars. This type should therefore be used with caution in contexts where conversion to other calendars is desired.

Note: See the conformance note in (§3.2.6) which applies to the year part of this datatype as well.

3.2.10.1 Lexical representation

The lexical representation for gYearMonth is the reduced (right truncated) lexical representation for dateTime: CCYY-MM. No left truncation is allowed. An optional following time zone qualifier is allowed. To accommodate year values outside the range from 0001 to 9999, additional digits can be added to the left of this representation and a preceding "-" sign is allowed.

For example, to indicate the month of May 1999, one would write: 1999-05. See also ISO 8601 Date and Time Formats (§D).

3.2.10.2 Constraining facets

gYearMonth has the following ·constraining facets·:

pattern
enumeration
whiteSpace
maxInclusive
maxExclusive
minInclusive
minExclusive

3.2.11 gYear

[Definition:] gYear represents a gregorian calendar year. The ·value space· of gYear is the set of Gregorian calendar years as defined in § 5.2.1 of [ISO 8601]. Specifically, it is a set of one-year long, non-periodic instances e.g. lexical 1999 to represent the whole year 1999, independent of how many months and days this year has.

Since the lexical representation allows an optional time zone indicator, gYear values are partially ordered because it may not be possible to unequivocally determine the order of two values one of which has a time zone and the other does not. If gYear values are considered as periods of time, the order relation on gYear values is the order relation on their starting instants. This is discussed in Order relation on dateTime (§3.2.7.4). See also Adding durations to dateTimes (§E). Pairs of gYear values with or without time zone indicators are totally ordered.

Note: Because years in one calendar only rarely correspond to years in other calendars, values of this type are not, in general, convertible to simple values corresponding to years in other calendars. This type should therefore be used with caution in contexts where conversion to other calendars is desired.

Note: See the conformance note in (§3.2.6) which applies to the year part of this datatype as well.

3.2.11.1 Lexical representation

The lexical representation for gYear is the reduced (right truncated) lexical representation for dateTime: CCYY. No left truncation is allowed. An optional following time zone qualifier is allowed as for dateTime. To accommodate year values outside the range from 0001 to 9999, additional digits can be added to the left of this representation and a preceding "-" sign is allowed.

For example, to indicate 1999, one would write: 1999. See also ISO 8601 Date and Time Formats (§D).

3.2.11.2 Constraining facets

gYear has the following ·constraining facets·:

pattern
enumeration
whiteSpace
maxInclusive
maxExclusive
minInclusive
minExclusive

3.2.12 gMonthDay

[Definition:] gMonthDay is a gregorian date that recurs, specifically a day of the year such as the third of May. Arbitrary recurring dates are not supported by this datatype. The ·value space· of gMonthDay is the set of calendar dates, as defined in § 3 of [ISO 8601]. Specifically, it is a set of one-day long, annually periodic instances.

Since the lexical representation allows an optional time zone indicator, gMonthDay values are partially ordered because it may not be possible to unequivocally determine the order of two values one of which has a time zone and the other does not. If gMonthDay values are considered as periods of time, in an arbitrary leap year, the order relation on gMonthDay values is the order relation on their starting instants. This is discussed in Order relation on dateTime (§3.2.7.4). See also Adding durations to dateTimes (§E). Pairs of gMonthDay values with or without time zone indicators are totally ordered.

Note: Because day/month combinations in one calendar only rarely correspond to day/month combinations in other calendars, values of this type do not, in general, have any straightforward or intuitive representation in terms of most other calendars. This type should therefore be used with caution in contexts where conversion to other calendars is desired.

3.2.12.1 Lexical representation

The lexical representation for gMonthDay is the left truncated lexical representation for date: --MM-DD. An optional following time zone qualifier is allowed as for date. No preceding sign is allowed. No other formats are allowed. See also ISO 8601 Date and Time Formats (§D).

This datatype can be used to represent a specific day in a month. To say, for example, that my birthday occurs on the 14th of September ever year.

3.2.12.2 Constraining facets

gMonthDay has the following ·constraining facets·:

pattern
enumeration
whiteSpace
maxInclusive
maxExclusive
minInclusive
minExclusive

3.2.13 gDay

[Definition:] gDay is a gregorian day that recurs, specifically a day of the month such as the 5th of the month. Arbitrary recurring days are not supported by this datatype. The ·value space· of gDay is the space of a set of calendar dates as defined in § 3 of [ISO 8601]. Specifically, it is a set of one-day long, monthly periodic instances.

This datatype can be used to represent a specific day of the month. To say, for example, that I get my paycheck on the 15th of each month.

Since the lexical representation allows an optional time zone indicator, gDay values are partially ordered because it may not be possible to unequivocally determine the order of two values one of which has a time zone and the other does not. If gDay values are considered as periods of time, in an arbitrary month that has 31 days, the order relation on gDay values is the order relation on their starting instants. This is discussed in Order relation on dateTime (§3.2.7.4). See also Adding durations to dateTimes (§E). Pairs of gDay values with or without time zone indicators are totally ordered.

Note: Because days in one calendar only rarely correspond to days in other calendars, values of this type do not, in general, have any straightforward or intuitive representation in terms of most other calendars. This type should therefore be used with caution in contexts where conversion to other calendars is desired.

3.2.13.1 Lexical representation

The lexical representation for gDay is the left truncated lexical representation for date: ---DD . An optional following time zone qualifier is allowed as for date. No preceding sign is allowed. No other formats are allowed. See also ISO 8601 Date and Time Formats (§D).

3.2.13.2 Constraining facets

gDay has the following ·constraining facets·:

pattern
enumeration
whiteSpace
maxInclusive
maxExclusive
minInclusive
minExclusive

3.2.14 gMonth

[Definition:] gMonth is a gregorian month that recurs every year. The ·value space· of gMonth is the space of a set of calendar months as defined in § 3 of [ISO 8601]. Specifically, it is a set of one-month long, yearly periodic instances.

This datatype can be used to represent a specific month. To say, for example, that Thanksgiving falls in the month of November.

Since the lexical representation allows an optional time zone indicator, gMonth values are partially ordered because it may not be possible to unequivocally determine the order of two values one of which has a time zone and the other does not. If gMonth values are considered as periods of time, the order relation on gMonth is the order relation on their starting instants. This is discussed in Order relation on dateTime (§3.2.7.4). See also Adding durations to dateTimes (§E). Pairs of gMonth values with or without time zone indicators are totally ordered.

Note: Because months in one calendar only rarely correspond to months in other calendars, values of this type do not, in general, have any straightforward or intuitive representation in terms of most other calendars. This type should therefore be used with caution in contexts where conversion to other calendars is desired.

3.2.14.1 Lexical representation

The lexical representation for gMonth is the left and right truncated lexical representation for date: --MM. An optional following time zone qualifier is allowed as for date. No preceding sign is allowed. No other formats are allowed. See also ISO 8601 Date and Time Formats (§D).

3.2.14.2 Constraining facets

gMonth has the following ·constraining facets·:

pattern
enumeration
whiteSpace
maxInclusive
maxExclusive
minInclusive
minExclusive

3.2.15 hexBinary

[Definition:] hexBinary represents arbitrary hex-encoded binary data. The ·value space· of hexBinary is the set of finite-length sequences of binary octets.

3.2.15.1 Lexical Representation

hexBinary has a lexical representation where each binary octet is encoded as a character tuple, consisting of two hexadecimal digits ([0-9a-fA-F]) representing the octet code. For example, "0FB7" is a hex encoding for the 16-bit integer 4023 (whose binary representation is 111110110111).

3.2.15.2 Canonical Representation

The canonical representation for hexBinary is defined by prohibiting certain options from the Lexical Representation (§3.2.15.1). Specifically, the lower case hexadecimal digits ([a-f]) are not allowed.

3.2.15.3 Constraining facets

hexBinary has the following ·constraining facets·:

length
minLength
maxLength
pattern
enumeration
whiteSpace

3.2.16 base64Binary

[Definition:] base64Binary represents Base64-encoded arbitrary binary data. The ·value space· of base64Binary is the set of finite-length sequences of binary octets. For base64Binary data the entire binary stream is encoded using the Base64 Alphabet in [RFC 2045].

The lexical forms of base64Binary values are limited to the 65 characters of the Base64 Alphabet defined in [RFC 2045], i.e., a-z, A-Z, 0-9, the plus sign (+), the forward slash (/) and the equal sign (=), together with the characters defined in [XML 1.0 (Second Edition)] as white space. No other characters are allowed.

For compatibility with older mail gateways, [RFC 2045] suggests that base64 data should have lines limited to at most 76 characters in length. This line-length limitation is not mandated in the lexical forms of base64Binary data and must not be enforced by XML Schema processors.

The lexical space of base64Binary is given by the following grammar (the notation is that used in [XML 1.0 (Second Edition)]); legal lexical forms must match the Base64Binary production.

Base64Binary ::= ((B64S B64S B64S B64S)* ((B64S B64S B64S B64) | (B64S B64S B16S '=') | (B64S B04S '=' #x20? '=')))? B64S ::= B64 #x20? B16S ::= B16 #x20? B04S ::= B04 #x20? B04 ::= [AQgw] B16 ::= [AEIMQUYcgkosw048] B64 ::= [A-Za-z0-9+/]

Note that this grammar requires the number of non-whitespace characters in the lexical form to be a multiple of four, and for equals signs to appear only at the end of the lexical form; strings which do not meet these constraints are not legal lexical forms of base64Binary because they cannot successfully be decoded by base64 decoders.

Note: The above definition of the lexical space is more restrictive than that given in [RFC 2045] as regards whitespace -- this is not an issue in practice. Any string compatible with the RFC can occur in an element or attribute validated by this type, because the ·whiteSpace · facet of this type is fixed to collapse, which means that all leading and trailing whitespace will be stripped, and all internal whitespace collapsed to single space characters, before the above grammar is enforced.

The canonical lexical form of a base64Binary data value is the base64 encoding of the value which matches the Canonical-base64Binary production in the following grammar:

Canonical-base64Binary ::= (B64 B64 B64 B64)* ((B64 B64 B16 '=') | (B64 B04 '=='))?

Note: For some values the canonical form defined above does not conform to [RFC 2045], which requires breaking with linefeeds at appropriate intervals.

The length of a base64Binary value is the number of octets it contains. This may be calculated from the lexical form by removing whitespace and padding characters and performing the calculation shown in the pseudo-code below:

lex2 := killwhitespace(lexform) -- remove whitespace characters lex3 := strip_equals(lex2) -- strip padding characters at end length := floor (length(lex3) * 3 / 4) -- calculate length

Note on encoding: [RFC 2045] explicitly references US-ASCII encoding. However, decoding of base64Binary data in an XML entity is to be performed on the Unicode characters obtained after character encoding processing as specified by [XML 1.0 (Second Edition)]

3.2.16.1 Constraining facets

base64Binary has the following ·constraining facets·:

length
minLength
maxLength
pattern
enumeration
whiteSpace

3.2.17 anyURI

[Definition:] anyURI represents a Uniform Resource Identifier Reference (URI). An anyURI value can be absolute or relative, and may have an optional fragment identifier (i.e., it may be a URI Reference). This type should be used to specify the intention that the value fulfills the role of a URI as defined by [RFC 2396], as amended by [RFC 2732].

The mapping from anyURI values to URIs is as defined by the URI reference escaping procedure defined in Section 5.4 Locator Attribute of [XML Linking Language] (see also Section 8 Character Encoding in URI References of [Character Model]). This means that a wide range of internationalized resource identifiers can be specified when an anyURI is called for, and still be understood as URIs per [RFC 2396], as amended by [RFC 2732], where appropriate to identify resources.

Note: Section 5.4 Locator Attribute of [XML Linking Language] requires that relative URI references be absolutized as defined in [XML Base] before use. This is an XLink-specific requirement and is not appropriate for XML Schema, since neither the ·lexical space · nor the ·value space · of the anyURI type are restricted to absolute URIs. Accordingly absolutization must not be performed by schema processors as part of schema validation.

Note: Each URI scheme imposes specialized syntax rules for URIs in that scheme, including restrictions on the syntax of allowed fragment identifiers. Because it is impractical for processors to check that a value is a context-appropriate URI reference, this specification follows the lead of [RFC 2396] (as amended by [RFC 2732]) in this matter: such rules and restrictions are not part of type validity and are not checked by ·minimally conforming · processors. Thus in practice the above definition imposes only very modest obligations on ·minimally conforming · processors.

3.2.17.1 Lexical representation

The ·lexical space· of anyURI is finite-length character sequences which, when the algorithm defined in Section 5.4 of [XML Linking Language] is applied to them, result in strings which are legal URIs according to [RFC 2396], as amended by [RFC 2732].

Note: Spaces are, in principle, allowed in the ·lexical space · of anyURI, however, their use is highly discouraged (unless they are encoded by %20).

3.2.17.2 Constraining facets

anyURI has the following ·constraining facets·:

length
minLength
maxLength
pattern
enumeration
whiteSpace

3.2.18 QName

[Definition:] QName represents XML qualified names. The ·value space· of QName is the set of tuples {namespace name, local part}, where namespace name is an anyURI and local part is an NCName. The ·lexical space· of QName is the set of strings that ·match· the QName production of [Namespaces in XML].

Note: The mapping between literals in the ·lexical space · and values in the ·value space · of QName requires a namespace declaration to be in scope for the context in which QName is used.

3.2.18.1 Constraining facets

QName has the following ·constraining facets·:

length
minLength
maxLength
pattern
enumeration
whiteSpace

The use of ·length·, ·minLength· and ·maxLength· on datatypes ·derived· from QName is deprecated. Future versions of this specification may remove these facets for this datatype.

3.2.19 NOTATION

[Definition:] NOTATION represents the NOTATION attribute type from [XML 1.0 (Second Edition)]. The ·value space· of NOTATION is the set of QNames of notations declared in the current schema. The ·lexical space· of NOTATION is the set of all names of notations declared in the current schema (in the form of QNames).

Schema Component Constraint: enumeration facet value required for NOTATION

It is an ·error · for NOTATION to be used directly in a schema. Only datatypes that are ·derived · from NOTATION by specifying a value for ·enumeration · can be used in a schema.

For compatibility (see Terminology (§1.4)) NOTATION should be used only on attributes and should only be used in schemas with no target namespace.

3.2.19.1 Constraining facets

NOTATION has the following ·constraining facets·:

length
minLength
maxLength
pattern
enumeration
whiteSpace

The use of ·length·, ·minLength· and ·maxLength· on datatypes ·derived· from NOTATION is deprecated. Future versions of this specification may remove these facets for this datatype.

3.3 Derived datatypes

        3.3.1 normalizedString
        3.3.2 token
        3.3.3 language
        3.3.4 NMTOKEN
        3.3.5 NMTOKENS
        3.3.6 Name
        3.3.7 NCName
        3.3.8 ID
        3.3.9 IDREF
        3.3.10 IDREFS
        3.3.11 ENTITY
        3.3.12 ENTITIES
        3.3.13 integer
        3.3.14 nonPositiveInteger
        3.3.15 negativeInteger
        3.3.16 long
        3.3.17 int
        3.3.18 short
        3.3.19 byte
        3.3.20 nonNegativeInteger
        3.3.21 unsignedLong
        3.3.22 unsignedInt
        3.3.23 unsignedShort
        3.3.24 unsignedByte
        3.3.25 positiveInteger

This section gives conceptual definitions for all ·built-in· ·derived· datatypes defined by this specification. The XML representation used to define ·derived· datatypes (whether ·built-in· or ·user-derived·) is given in section XML Representation of Simple Type Definition Schema Components (§4.1.2) and the complete definitions of the ·built-in· ·derived· datatypes are provided in Appendix A Schema for Datatype Definitions (normative) (§A).

3.3.1 normalizedString

[Definition:] normalizedString represents white space normalized strings. The ·value space· of normalizedString is the set of strings that do not contain the carriage return (#xD), line feed (#xA) nor tab (#x9) characters. The ·lexical space· of normalizedString is the set of strings that do not contain the carriage return (#xD), line feed (#xA) nor tab (#x9) characters. The ·base type· of normalizedString is string.

3.3.1.1 Constraining facets

normalizedString has the following ·constraining facets·:

length
minLength
maxLength
pattern
enumeration
whiteSpace

3.3.1.2 Derived datatypes

The following ·built-in· datatypes are ·derived· from normalizedString:

token

3.3.2 token

[Definition:] token represents tokenized strings. The ·value space· of token is the set of strings that do not contain the carriage return (#xD), line feed (#xA) nor tab (#x9) characters, that have no leading or trailing spaces (#x20) and that have no internal sequences of two or more spaces. The ·lexical space· of token is the set of strings that do not contain the carriage return (#xD), line feed (#xA) nor tab (#x9) characters, that have no leading or trailing spaces (#x20) and that have no internal sequences of two or more spaces. The ·base type· of token is normalizedString.

3.3.2.1 Constraining facets

token has the following ·constraining facets·:

length
minLength
maxLength
pattern
enumeration
whiteSpace

3.3.2.2 Derived datatypes

The following ·built-in· datatypes are ·derived· from token:

language
NMTOKEN
Name

3.3.3 language

[Definition:] language represents natural language identifiers as defined by by [RFC 3066] . The ·value space· of language is the set of all strings that are valid language identifiers as defined [RFC 3066] . The ·lexical space· of language is the set of all strings that conform to the pattern [a-zA-Z]{1,8}(-[a-zA-Z0-9]{1,8})* . The ·base type· of language is token.

3.3.3.1 Constraining facets

language has the following ·constraining facets·:

length
minLength
maxLength
pattern
enumeration
whiteSpace

3.3.4 NMTOKEN

[Definition:] NMTOKEN represents the NMTOKEN attribute type from [XML 1.0 (Second Edition)]. The ·value space· of NMTOKEN is the set of tokens that ·match· the Nmtoken production in [XML 1.0 (Second Edition)]. The ·lexical space· of NMTOKEN is the set of strings that ·match· the Nmtoken production in [XML 1.0 (Second Edition)]. The ·base type· of NMTOKEN is token.

For compatibility (see Terminology (§1.4)) NMTOKEN should be used only on attributes.

3.3.4.1 Constraining facets

NMTOKEN has the following ·constraining facets·:

length
minLength
maxLength
pattern
enumeration
whiteSpace

3.3.4.2 Derived datatypes

The following ·built-in· datatypes are ·derived· from NMTOKEN:

NMTOKENS

3.3.5 NMTOKENS

[Definition:] NMTOKENS represents the NMTOKENS attribute type from [XML 1.0 (Second Edition)]. The ·value space· of NMTOKENS is the set of finite, non-zero-length sequences of ·NMTOKEN·s. The ·lexical space· of NMTOKENS is the set of space-separated lists of tokens, of which each token is in the ·lexical space· of NMTOKEN. The ·itemType· of NMTOKENS is NMTOKEN.

For compatibility (see Terminology (§1.4)) NMTOKENS should be used only on attributes.

3.3.5.1 Constraining facets

NMTOKENS has the following ·constraining facets·:

length
minLength
maxLength
enumeration
whiteSpace
pattern

3.3.6 Name

[Definition:] Name represents XML Names. The ·value space· of Name is the set of all strings which ·match· the Name production of [XML 1.0 (Second Edition)]. The ·lexical space· of Name is the set of all strings which ·match· the Name production of [XML 1.0 (Second Edition)]. The ·base type· of Name is token.

3.3.6.1 Constraining facets

Name has the following ·constraining facets·:

length
minLength
maxLength
pattern
enumeration
whiteSpace

3.3.6.2 Derived datatypes

The following ·built-in· datatypes are ·derived· from Name:

NCName

3.3.7 NCName

[Definition:] NCName represents XML "non-colonized" Names. The ·value space· of NCName is the set of all strings which ·match· the NCName production of [Namespaces in XML]. The ·lexical space· of NCName is the set of all strings which ·match· the NCName production of [Namespaces in XML]. The ·base type· of NCName is Name.

3.3.7.1 Constraining facets

NCName has the following ·constraining facets·:

length
minLength
maxLength
pattern
enumeration
whiteSpace

3.3.7.2 Derived datatypes

The following ·built-in· datatypes are ·derived· from NCName:

ID
IDREF
ENTITY

3.3.8 ID

[Definition:] ID represents the ID attribute type from [XML 1.0 (Second Edition)]. The ·value space· of ID is the set of all strings that ·match· the NCName production in [Namespaces in XML]. The ·lexical space· of ID is the set of all strings that ·match· the NCName production in [Namespaces in XML]. The ·base type· of ID is NCName.

For compatibility (see Terminology (§1.4)) ID should be used only on attributes.

3.3.8.1 Constraining facets

ID has the following ·constraining facets·:

length
minLength
maxLength
pattern
enumeration
whiteSpace

3.3.9 IDREF

[Definition:] IDREF represents the IDREF attribute type from [XML 1.0 (Second Edition)]. The ·value space· of IDREF is the set of all strings that ·match· the NCName production in [Namespaces in XML]. The ·lexical space· of IDREF is the set of strings that ·match· the NCName production in [Namespaces in XML]. The ·base type· of IDREF is NCName.

For compatibility (see Terminology (§1.4)) this datatype should be used only on attributes.

3.3.9.1 Constraining facets

IDREF has the following ·constraining facets·:

length
minLength
maxLength
pattern
enumeration
whiteSpace

3.3.9.2 Derived datatypes

The following ·built-in· datatypes are ·derived· from IDREF:

IDREFS

3.3.10 IDREFS

[Definition:] IDREFS represents the IDREFS attribute type from [XML 1.0 (Second Edition)]. The ·value space· of IDREFS is the set of finite, non-zero-length sequences of IDREFs. The ·lexical space· of IDREFS is the set of space-separated lists of tokens, of which each token is in the ·lexical space· of IDREF. The ·itemType· of IDREFS is IDREF.

For compatibility (see Terminology (§1.4)) IDREFS should be used only on attributes.

3.3.10.1 Constraining facets

IDREFS has the following ·constraining facets·:

length
minLength
maxLength
enumeration
whiteSpace
pattern

3.3.11 ENTITY

[Definition:] ENTITY represents the ENTITY attribute type from [XML 1.0 (Second Edition)]. The ·value space· of ENTITY is the set of all strings that ·match· the NCName production in [Namespaces in XML] and have been declared as an unparsed entity in a document type definition. The ·lexical space· of ENTITY is the set of all strings that ·match· the NCName production in [Namespaces in XML]. The ·base type· of ENTITY is NCName.

Note: The ·value space · of ENTITY is scoped to a specific instance document.

For compatibility (see Terminology (§1.4)) ENTITY should be used only on attributes.

3.3.11.1 Constraining facets

ENTITY has the following ·constraining facets·:

length
minLength
maxLength
pattern
enumeration
whiteSpace

3.3.11.2 Derived datatypes

The following ·built-in· datatypes are ·derived· from ENTITY:

ENTITIES

3.3.12 ENTITIES

[Definition:] ENTITIES represents the ENTITIES attribute type from [XML 1.0 (Second Edition)]. The ·value space· of ENTITIES is the set of finite, non-zero-length sequences of ·ENTITY·s that have been declared as unparsed entities in a document type definition. The ·lexical space· of ENTITIES is the set of space-separated lists of tokens, of which each token is in the ·lexical space· of ENTITY. The ·itemType· of ENTITIES is ENTITY.

Note: The ·value space · of ENTITIES is scoped to a specific instance document.

For compatibility (see Terminology (§1.4)) ENTITIES should be used only on attributes.

3.3.12.1 Constraining facets

ENTITIES has the following ·constraining facets·:

length
minLength
maxLength
enumeration
whiteSpace
pattern

3.3.13 integer

[Definition:] integer is ·derived· from decimal by fixing the value of ·fractionDigits· to be 0and disallowing the trailing decimal point. This results in the standard mathematical concept of the integer numbers. The ·value space· of integer is the infinite set {...,-2,-1,0,1,2,...}. The ·base type· of integer is decimal.

3.3.13.1 Lexical representation

integer has a lexical representation consisting of a finite-length sequence of decimal digits (#x30-#x39) with an optional leading sign. If the sign is omitted, "+" is assumed. For example: -1, 0, 12678967543233, +100000.

3.3.13.2 Canonical representation

The canonical representation for integer is defined by prohibiting certain options from the Lexical representation (§3.3.13.1). Specifically, the preceding optional "+" sign is prohibited and leading zeroes are prohibited.

3.3.13.3 Constraining facets

integer has the following ·constraining facets·:

totalDigits
fractionDigits
pattern
whiteSpace
enumeration
maxInclusive
maxExclusive
minInclusive
minExclusive

3.3.13.4 Derived datatypes

The following ·built-in· datatypes are ·derived· from integer:

nonPositiveInteger
long
nonNegativeInteger

3.3.14 nonPositiveInteger

[Definition:] nonPositiveInteger is ·derived· from integer by setting the value of ·maxInclusive· to be 0. This results in the standard mathematical concept of the non-positive integers. The ·value space· of nonPositiveInteger is the infinite set {...,-2,-1,0}. The ·base type· of nonPositiveInteger is integer.

3.3.14.1 Lexical representation

nonPositiveInteger has a lexical representation consisting of an optional preceding sign followed by a finite-length sequence of decimal digits (#x30-#x39). The sign may be "+" or may be omitted only for lexical forms denoting zero; in all other lexical forms, the negative sign ("-") must be present. For example: -1, 0, -12678967543233, -100000.

3.3.14.2 Canonical representation

The canonical representation for nonPositiveInteger is defined by prohibiting certain options from the Lexical representation (§3.3.14.1). In the canonical form for zero, the sign must be omitted. Leading zeroes are prohibited.

3.3.14.3 Constraining facets

nonPositiveInteger has the following ·constraining facets·:

totalDigits
fractionDigits
pattern
whiteSpace
enumeration
maxInclusive
maxExclusive
minInclusive
minExclusive

3.3.14.4 Derived datatypes

The following ·built-in· datatypes are ·derived· from nonPositiveInteger:

negativeInteger

3.3.15 negativeInteger

[Definition:] negativeInteger is ·derived· from nonPositiveInteger by setting the value of ·maxInclusive· to be -1. This results in the standard mathematical concept of the negative integers. The ·value space· of negativeInteger is the infinite set {...,-2,-1}. The ·base type· of negativeInteger is nonPositiveInteger.

3.3.15.1 Lexical representation

negativeInteger has a lexical representation consisting of a negative sign ("-") followed by a finite-length sequence of decimal digits (#x30-#x39). For example: -1, -12678967543233, -100000.

3.3.15.2 Canonical representation

The canonical representation for negativeInteger is defined by prohibiting certain options from the Lexical representation (§3.3.15.1). Specifically, leading zeroes are prohibited.

3.3.15.3 Constraining facets

negativeInteger has the following ·constraining facets·:

totalDigits
fractionDigits
pattern
whiteSpace
enumeration
maxInclusive
maxExclusive
minInclusive
minExclusive

3.3.16 long

[Definition:] long is ·derived· from integer by setting the value of ·maxInclusive· to be 9223372036854775807 and ·minInclusive· to be -9223372036854775808. The ·base type· of long is integer.

3.3.16.1 Lexical representation

long has a lexical representation consisting of an optional sign followed by a finite-length sequence of decimal digits (#x30-#x39). If the sign is omitted, "+" is assumed. For example: -1, 0, 12678967543233, +100000.

3.3.16.2 Canonical representation

The canonical representation for long is defined by prohibiting certain options from the Lexical representation (§3.3.16.1). Specifically, the the optional "+" sign is prohibited and leading zeroes are prohibited.

3.3.16.3 Constraining facets

long has the following ·constraining facets·:

totalDigits
fractionDigits
pattern
whiteSpace
enumeration
maxInclusive
maxExclusive
minInclusive
minExclusive

3.3.16.4 Derived datatypes

The following ·built-in· datatypes are ·derived· from long:

3.3.17 int

[Definition:] int is ·derived· from long by setting the value of ·maxInclusive· to be 2147483647 and ·minInclusive· to be -2147483648. The ·base type· of int is long.

3.3.17.1 Lexical representation

int has a lexical representation consisting of an optional sign followed by a finite-length sequence of decimal digits (#x30-#x39). If the sign is omitted, "+" is assumed. For example: -1, 0, 126789675, +100000.

3.3.17.2 Canonical representation

The canonical representation for int is defined by prohibiting certain options from the Lexical representation (§3.3.17.1). Specifically, the the optional "+" sign is prohibited and leading zeroes are prohibited.

3.3.17.3 Constraining facets

int has the following ·constraining facets·:

totalDigits
fractionDigits
pattern
whiteSpace
enumeration
maxInclusive
maxExclusive
minInclusive
minExclusive

3.3.17.4 Derived datatypes

The following ·built-in· datatypes are ·derived· from int:

short

3.3.18 short

[Definition:] short is ·derived· from int by setting the value of ·maxInclusive· to be 32767 and ·minInclusive· to be -32768. The ·base type· of short is int.

3.3.18.1 Lexical representation

short has a lexical representation consisting of an optional sign followed by a finite-length sequence of decimal digits (#x30-#x39). If the sign is omitted, "+" is assumed. For example: -1, 0, 12678, +10000.

3.3.18.2 Canonical representation

The canonical representation for short is defined by prohibiting certain options from the Lexical representation (§3.3.18.1). Specifically, the the optional "+" sign is prohibited and leading zeroes are prohibited.

3.3.18.3 Constraining facets

short has the following ·constraining facets·:

totalDigits
fractionDigits
pattern
whiteSpace
enumeration
maxInclusive
maxExclusive
minInclusive
minExclusive

3.3.18.4 Derived datatypes

The following ·built-in· datatypes are ·derived· from short:

byte

3.3.19 byte

[Definition:] byte is ·derived· from short by setting the value of ·maxInclusive· to be 127 and ·minInclusive· to be -128. The ·base type· of byte is short.

3.3.19.1 Lexical representation

byte has a lexical representation consisting of an optional sign followed by a finite-length sequence of decimal digits (#x30-#x39). If the sign is omitted, "+" is assumed. For example: -1, 0, 126, +100.

3.3.19.2 Canonical representation

The canonical representation for byte is defined by prohibiting certain options from the Lexical representation (§3.3.19.1). Specifically, the the optional "+" sign is prohibited and leading zeroes are prohibited.

3.3.19.3 Constraining facets

byte has the following ·constraining facets·:

totalDigits
fractionDigits
pattern
whiteSpace
enumeration
maxInclusive
maxExclusive
minInclusive
minExclusive

3.3.20 nonNegativeInteger

[Definition:] nonNegativeInteger is ·derived· from integer by setting the value of ·minInclusive· to be 0. This results in the standard mathematical concept of the non-negative integers. The ·value space· of nonNegativeInteger is the infinite set {0,1,2,...}. The ·base type· of nonNegativeInteger is integer.

3.3.20.1 Lexical representation

nonNegativeInteger has a lexical representation consisting of an optional sign followed by a finite-length sequence of decimal digits (#x30-#x39). If the sign is omitted, the positive sign ("+") is assumed. If the sign is present, it must be "+" except for lexical forms denoting zero, which may be preceded by a positive ("+") or a negative ("-") sign. For example: 1, 0, 12678967543233, +100000.

3.3.20.2 Canonical representation

The canonical representation for nonNegativeInteger is defined by prohibiting certain options from the Lexical representation (§3.3.20.1). Specifically, the the optional "+" sign is prohibited and leading zeroes are prohibited.

3.3.20.3 Constraining facets

nonNegativeInteger has the following ·constraining facets·:

totalDigits
fractionDigits
pattern
whiteSpace
enumeration
maxInclusive
maxExclusive
minInclusive
minExclusive

3.3.20.4 Derived datatypes

The following ·built-in· datatypes are ·derived· from nonNegativeInteger:

unsignedLong
positiveInteger

3.3.21 unsignedLong

[Definition:] unsignedLong is ·derived· from nonNegativeInteger by setting the value of ·maxInclusive· to be 18446744073709551615. The ·base type· of unsignedLong is nonNegativeInteger.

3.3.21.1 Lexical representation

unsignedLong has a lexical representation consisting of a finite-length sequence of decimal digits (#x30-#x39). For example: 0, 12678967543233, 100000.

3.3.21.2 Canonical representation

The canonical representation for unsignedLong is defined by prohibiting certain options from the Lexical representation (§3.3.21.1). Specifically, leading zeroes are prohibited.

3.3.21.3 Constraining facets

unsignedLong has the following ·constraining facets·:

totalDigits
fractionDigits
pattern
whiteSpace
enumeration
maxInclusive
maxExclusive
minInclusive
minExclusive

3.3.21.4 Derived datatypes

The following ·built-in· datatypes are ·derived· from unsignedLong:

unsignedInt

3.3.22 unsignedInt

[Definition:] unsignedInt is ·derived· from unsignedLong by setting the value of ·maxInclusive· to be 4294967295. The ·base type· of unsignedInt is unsignedLong.

3.3.22.1 Lexical representation

unsignedInt has a lexical representation consisting of a finite-length sequence of decimal digits (#x30-#x39). For example: 0, 1267896754, 100000.

3.3.22.2 Canonical representation

The canonical representation for unsignedInt is defined by prohibiting certain options from the Lexical representation (§3.3.22.1). Specifically, leading zeroes are prohibited.

3.3.22.3 Constraining facets

unsignedInt has the following ·constraining facets·:

totalDigits
fractionDigits
pattern
whiteSpace
enumeration
maxInclusive
maxExclusive
minInclusive
minExclusive

3.3.22.4 Derived datatypes

The following ·built-in· datatypes are ·derived· from unsignedInt:

unsignedShort

3.3.23 unsignedShort

[Definition:] unsignedShort is ·derived· from unsignedInt by setting the value of ·maxInclusive· to be 65535. The ·base type· of unsignedShort is unsignedInt.

3.3.23.1 Lexical representation

unsignedShort has a lexical representation consisting of a finite-length sequence of decimal digits (#x30-#x39). For example: 0, 12678, 10000.

3.3.23.2 Canonical representation

The canonical representation for unsignedShort is defined by prohibiting certain options from the Lexical representation (§3.3.23.1). Specifically, the leading zeroes are prohibited.

3.3.23.3 Constraining facets

unsignedShort has the following ·constraining facets·:

totalDigits
fractionDigits
pattern
whiteSpace
enumeration
maxInclusive
maxExclusive
minInclusive
minExclusive

3.3.23.4 Derived datatypes

The following ·built-in· datatypes are ·derived· from unsignedShort:

unsignedByte

3.3.24 unsignedByte

[Definition:] unsignedByte is ·derived· from unsignedShort by setting the value of ·maxInclusive· to be 255. The ·base type· of unsignedByte is unsignedShort.

3.3.24.1 Lexical representation

unsignedByte has a lexical representation consisting of a finite-length sequence of decimal digits (#x30-#x39). For example: 0, 126, 100.

3.3.24.2 Canonical representation

The canonical representation for unsignedByte is defined by prohibiting certain options from the Lexical representation (§3.3.24.1). Specifically, leading zeroes are prohibited.

3.3.24.3 Constraining facets

unsignedByte has the following ·constraining facets·:

totalDigits
fractionDigits
pattern
whiteSpace
enumeration
maxInclusive
maxExclusive
minInclusive
minExclusive

3.3.25 positiveInteger

[Definition:] positiveInteger is ·derived· from nonNegativeInteger by setting the value of ·minInclusive· to be 1. This results in the standard mathematical concept of the positive integer numbers. The ·value space· of positiveInteger is the infinite set {1,2,...}. The ·base type· of positiveInteger is nonNegativeInteger.

3.3.25.1 Lexical representation

positiveInteger has a lexical representation consisting of an optional positive sign ("+") followed by a finite-length sequence of decimal digits (#x30-#x39). For example: 1, 12678967543233, +100000.

3.3.25.2 Canonical representation

The canonical representation for positiveInteger is defined by prohibiting certain options from the Lexical representation (§3.3.25.1). Specifically, the optional "+" sign is prohibited and leading zeroes are prohibited.

3.3.25.3 Constraining facets

positiveInteger has the following ·constraining facets·:

totalDigits
fractionDigits
pattern
whiteSpace
enumeration
maxInclusive
maxExclusive
minInclusive
minExclusive

4 Datatype components

The following sections provide full details on the properties and significance of each kind of schema component involved in datatype definitions. For each property, the kinds of values it is allowed to have is specified. Any property not identified as optional is required to be present; optional properties which are not present have absent as their value. Any property identified as a having a set, subset or ·list· value may have an empty value unless this is explicitly ruled out: this is not the same as absent. Any property value identified as a superset or a subset of some set may be equal to that set, unless a proper superset or subset is explicitly called for.

For more information on the notion of datatype (schema) components, see Schema Component Details of [XML Schema Part 1: Structures].

4.1 Simple Type Definition

        4.1.1 The Simple Type Definition Schema Component
        4.1.2 XML Representation of Simple Type Definition Schema Components
        4.1.3 Constraints on XML Representation of Simple Type Definition
        4.1.4 Simple Type Definition Validation Rules
        4.1.5 Constraints on Simple Type Definition Schema Components
        4.1.6 Simple Type Definition for anySimpleType

Simple Type definitions provide for:

Establishing the ·value space· and ·lexical space· of a datatype, through the combined set of ·constraining facet·s specified in the definition;
Attaching a unique name (actually a QName) to the ·value space· and ·lexical space·.

4.1.1 The Simple Type Definition Schema Component

The Simple Type Definition schema component has the following properties:

Schema Component : Simple Type Definition

{name}

Optional. An NCName as defined by [Namespaces in XML].

{target namespace}

Either absent or a namespace name, as defined in [Namespaces in XML].

{variety}

One of { atomic, list, union}. Depending on the value of {variety}, further properties are defined as follows:

atomic

{primitive type definition}: A ·built-in · ·primitive · datatype definition).

list

{item type definition}: An ·atomic · or ·union · simple type definition.

union

{member type definitions}: A non-empty sequence of simple type definitions.

{facets}

A possibly empty set of Facets (§2.4).

{fundamental facets}

A set of Fundamental facets (§2.4.1)

{base type definition}

If the datatype has been ·derived · by ·restriction · then the Simple Type Definition component from which it is ·derived ·, otherwise the Simple Type Definition for anySimpleType (§4.1.6).

{final}

A subset of {restriction, list, union}.

{annotation}

Optional. An annotation.

Datatypes are identified by their {name} and {target namespace}. Except for anonymous datatypes (those with no {name}), datatype definitions ·must· be uniquely identified within a schema.

If {variety} is ·atomic· then the ·value space· of the datatype defined will be a subset of the ·value space· of {base type definition} (which is a subset of the ·value space· of {primitive type definition}). If {variety} is ·list· then the ·value space· of the datatype defined will be the set of finite-length sequence of values from the ·value space· of {item type definition}. If {variety} is ·union· then the ·value space· of the datatype defined will be the union of the ·value space·s of each datatype in {member type definitions}.

If {variety} is ·atomic· then the {variety} of {base type definition} must be ·atomic·. If {variety} is ·list· then the {variety} of {item type definition} must be either ·atomic· or ·union·. If {variety} is ·union· then {member type definitions} must be a list of datatype definitions.

The value of {facets} consists of the set of ·facet·s specified directly in the datatype definition unioned with the possibly empty set of {facets} of {base type definition}.

The value of {fundamental facets} consists of the set of ·fundamental facet·s and their values.

If {final} is the empty set then the type can be used in deriving other types; the explicit values restriction, list and union prevent further derivations by ·restriction·, ·list· and ·union· respectively.

4.1.2 XML Representation of Simple Type Definition Schema Components

The XML representation for a Simple Type Definition schema component is a element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation Summary: simpleType Element Information Item

  final = (#all | List of (list | union | restriction))
  id = ID
  name = NCName
  {any attributes with non-schema namespace . . .}>
  Content: (annotation?, (restriction | list | union))

Datatype Definition Schema Component

Property	Representation
{name}	The actual value of the `name` [attribute], if present, otherwise null
{final}	A set corresponding to the actual value of the `final` [attribute], if present, otherwise the actual value of the `finalDefault` [attribute] of the ancestor schema element information item, if present, otherwise the empty string, as follows: the empty string the empty set; `#all` {restriction, list, union}; otherwise a set with members drawn from the set above, each being present or absent depending on whether the string contains an equivalently named space-delimited substring. Note: Although the `finalDefault` [attribute] of schema may include values other than restriction, list or union, those values are ignored in the determination of {final}
{target namespace}	The actual value of the `targetNamespace` [attribute] of the parent `schema` element information item.
{annotation}	The annotation corresponding to the element information item in the [children], if present, otherwise null

A ·derived· datatype can be ·derived· from a ·primitive· datatype or another ·derived· datatype by one of three means: by restriction, by list or by union.

4.1.2.1 Derivation by restriction

XML Representation Summary : restriction Element Information Item

  base = QName
  id = ID
  {any attributes with non-schema namespace . . .}>
  Content: (annotation?, (simpleType?, (minExclusive | minInclusive | maxExclusive | maxInclusive | totalDigits | fractionDigits | length | minLength | maxLength | enumeration | whiteSpace | pattern)*))

Simple Type Definition Schema Component

Property	Representation
{variety}	The actual value of {variety} of {base type definition}
{facets}	The union of the set of Facets (§2.4) components resolved to by the facet [children] merged with {facets} from {base type definition}, subject to the Facet Restriction Valid constraints specified in Facets (§2.4).
{base type definition}	The Simple Type Definition component resolved to by the actual value of the `base` [attribute] or the [children], whichever is present.

Example

An electronic commerce schema might define a datatype called Sku (the barcode number that appears on products) from the ·built-in · datatype string by supplying a value for the ·pattern · facet.

In this case, Sku is the name of the new ·user-derived · datatype, string is its ·base type · and ·pattern · is the facet.

4.1.2.2 Derivation by list

XML Representation Summary : list Element Information Item

  id = ID
  itemType = QName
  {any attributes with non-schema namespace . . .}>
  Content: (annotation?, simpleType?)

Simple Type Definition Schema Component

Property	Representation
{variety}	list
{item type definition}	The Simple Type Definition component resolved to by the actual value of the `itemType` [attribute] or the [children], whichever is present.

A ·list· datatype must be ·derived· from an ·atomic· or a ·union· datatype, known as the ·itemType· of the ·list· datatype. This yields a datatype whose ·value space· is composed of finite-length sequences of values from the ·value space· of the ·itemType· and whose ·lexical space· is composed of space-separated lists of literals of the ·itemType·.

Example

A system might want to store lists of floating point values.

In this case, listOfFloat is the name of the new ·user-derived · datatype, float is its ·itemType · and ·list · is the derivation method.

As mentioned in List datatypes (§2.5.1.2), when a datatype is ·derived· from a ·list· datatype, the following ·constraining facet·s can be used:

·length·
·maxLength·
·minLength·
·enumeration·
·pattern·
·whiteSpace·

regardless of the ·constraining facet·s that are applicable to the ·atomic· datatype that serves as the ·itemType· of the ·list·.

For each of ·length·, ·maxLength· and ·minLength·, the unit of length is measured in number of list items. The value of ·whiteSpace· is fixed to the value collapse.

4.1.2.3 Derivation by union

XML Representation Summary : union Element Information Item

  id = ID
  memberTypes = List of QName
  {any attributes with non-schema namespace . . .}>
  Content: (annotation?, simpleType*)

Simple Type Definition Schema Component

Property Representation

{variety} union

{member type definitions} The sequence of Simple Type Definition components resolved to by the items in the actual value of the memberTypes [attribute], if any, in order, followed by the Simple Type Definition components resolved to by the [children], if any, in order. If {variety} is union for any Simple Type Definition components resolved to above, then the Simple Type Definition is replaced by its {member type definitions}.

A ·union· datatype can be ·derived· from one or more ·atomic·, ·list· or other ·union· datatypes, known as the ·memberTypes· of that ·union· datatype.

Example

As an example, taken from a typical display oriented text markup language, one might want to express font sizes as an integer between 8 and 72, or with one of the tokens "small", "medium" or "large". The ·union · type definition below would accomplish that.

A header

this is a test

As mentioned in Union datatypes (§2.5.1.3), when a datatype is ·derived· from a ·union· datatype, the only following ·constraining facet·s can be used:

·pattern·
·enumeration·

regardless of the ·constraining facet·s that are applicable to the datatypes that participate in the ·union·

4.1.3 Constraints on XML Representation of Simple Type Definition

Schema Representation Constraint: Single Facet Value

Unless otherwise specifically allowed by this specification ( Multiple patterns (§4.3.4.3) and Multiple enumerations (§4.3.5.3)) any given ·constraining facet · can only be specifed once within a single derivation step.

Schema Representation Constraint: itemType attribute or simpleType child

Either the itemType [attribute] or the [child] of the element must be present, but not both.

Schema Representation Constraint: base attribute or simpleType child

Either the base [attribute] or the simpleType [child] of the element must be present, but not both.

Schema Representation Constraint: memberTypes attribute or simpleType children

Either the memberTypes [attribute] of the element must be non-empty or there must be at least one simpleType [child].

4.1.4 Simple Type Definition Validation Rules

Validation Rule: Facet Valid

A value in a ·value space · is facet-valid with respect to a ·constraining facet · component if:

1 the value is facet-valid with respect to the particular ·constraining facet · as specified below.

Validation Rule: Datatype Valid

A string is datatype-valid with respect to a datatype definition if:

1 it ·match ·es a literal in the ·lexical space · of the datatype, determined as follows:

1.1 if ·pattern · is a member of {facets}, then the string must be pattern valid (§4.3.4.4);

1.2 if ·pattern · is not a member of {facets}, then

1.2.1 if {variety} is ·atomic · then the string must ·match · a literal in the ·lexical space · of {base type definition}

1.2.2 if {variety} is ·list · then the string must be a sequence of space-separated tokens, each of which ·match ·es a literal in the ·lexical space · of {item type definition}

1.2.3 if {variety} is ·union · then the string must ·match · a literal in the ·lexical space · of at least one member of {member type definitions}

2 the value denoted by the literal ·match ·ed in the previous step is a member of the ·value space · of the datatype, as determined by it being Facet Valid (§4.1.4) with respect to each member of {facets} (except for ·pattern ·).

4.1.5 Constraints on Simple Type Definition Schema Components

Schema Component Constraint: applicable facets

The ·constraining facet ·s which are allowed to be members of {facets} are dependent on {base type definition} as specified in the following table:

{base type definition}	applicable {facets}
If {variety} is list, then
[all datatypes]	length, minLength, maxLength, pattern, enumeration, whiteSpace
If {variety} is union, then
[all datatypes]	pattern, enumeration
else if {variety} is atomic, then
string	length, minLength, maxLength, pattern, enumeration, whiteSpace
boolean	pattern, whiteSpace
float	pattern, enumeration, whiteSpace, maxInclusive, maxExclusive, minInclusive, minExclusive
double	pattern, enumeration, whiteSpace, maxInclusive, maxExclusive, minInclusive, minExclusive
decimal	totalDigits, fractionDigits, pattern, whiteSpace, enumeration, maxInclusive, maxExclusive, minInclusive, minExclusive
duration	pattern, enumeration, whiteSpace, maxInclusive, maxExclusive, minInclusive, minExclusive
dateTime	pattern, enumeration, whiteSpace, maxInclusive, maxExclusive, minInclusive, minExclusive
time	pattern, enumeration, whiteSpace, maxInclusive, maxExclusive, minInclusive, minExclusive
date	pattern, enumeration, whiteSpace, maxInclusive, maxExclusive, minInclusive, minExclusive
gYearMonth	pattern, enumeration, whiteSpace, maxInclusive, maxExclusive, minInclusive, minExclusive
gYear	pattern, enumeration, whiteSpace, maxInclusive, maxExclusive, minInclusive, minExclusive
gMonthDay	pattern, enumeration, whiteSpace, maxInclusive, maxExclusive, minInclusive, minExclusive
gDay	pattern, enumeration, whiteSpace, maxInclusive, maxExclusive, minInclusive, minExclusive
gMonth	pattern, enumeration, whiteSpace, maxInclusive, maxExclusive, minInclusive, minExclusive
hexBinary	length, minLength, maxLength, pattern, enumeration, whiteSpace
base64Binary	length, minLength, maxLength, pattern, enumeration, whiteSpace
anyURI	length, minLength, maxLength, pattern, enumeration, whiteSpace
QName	length, minLength, maxLength, pattern, enumeration, whiteSpace
NOTATION	length, minLength, maxLength, pattern, enumeration, whiteSpace

Schema Component Constraint: list of atomic

If {variety} is ·list ·, then the {variety} of {item type definition} ·must · be ·atomic · or ·union ·.

Schema Component Constraint: no circular unions

If {variety} is ·union ·, then it is an ·error · if {name} and {target namespace} ·match · {name} and {target namespace} of any member of {member type definitions}.

4.1.6 Simple Type Definition for anySimpleType

There is a simple type definition nearly equivalent to the simple version of the ur-type definition present in every schema by definition. It has the following properties:

Schema Component: anySimpleType

{name}: anySimpleType
{target namespace}: http://www.w3.org/2001/XMLSchema
{basetype definition}: the ur-type definition
{final}: the empty set
{variety}: absent

4.2 Fundamental Facets

        4.2.1 equal
        4.2.2 ordered
        4.2.3 bounded
        4.2.4 cardinality
        4.2.5 numeric

4.2.1 equal

Every ·value space· supports the notion of equality, with the following rules:

for any a and b in the ·value space·, either a is equal to b, denoted a = b, or a is not equal to b, denoted a != b
there is no pair a and b from the ·value space· such that both a = b and a != b
for all a in the ·value space·, a = a
for any a and b in the ·value space·, a = b if and only if b = a
for any a, b and c in the ·value space·, if a = b and b = c, then a = c
for any a and b in the ·value space· if a = b, then a and b cannot be distinguished (i.e., equality is identity)
the ·value space·s of all ·primitive· datatypes are disjoint (they do not share any values)

On every datatype, the operation Equal is defined in terms of the equality property of the ·value space·: for any values a, b drawn from the ·value space·, Equal(a,b) is true if a = b, and false otherwise.

Note that in consequence of the above:

given ·value space· A and ·value space· B where A and B are disjoint, every pair of values a from A and b from B, a != b
two values which are members of the ·value space· of the same ·primitive· datatype may always be compared with each other
if a datatype T is ·derived· by ·union· from ·memberTypes· A, B, ... then the ·value space· of T is the union of ·value space·s of its ·memberTypes· A, B, .... Some values in the ·value space· of T are also values in the ·value space· of A. Other values in the ·value space· of T will be values in the ·value space· of B and so on. Values in the ·value space· of T which are also in the ·value space· of A can be compared with other values in the ·value space· of A according to the above rules. Similarly for values of type T and B and all the other ·memberTypes·.
if a datatype T' is ·derived· by ·restriction· from an atomic datatype T then the ·value space· of T' is a subset of the ·value space· of T. Values in the ·value space·s of T and T' can be compared according to the above rules
if datatypes T' and T'' are ·derived· by ·restriction· from a common atomic ancestor T then the ·value space·s of T' and T'' may overlap. Values in the ·value space·s of T' and T'' can be compared according to the above rules

Note: There is no schema component corresponding to the equal ·fundamental facet ·.

4.2.2 ordered

[Definition:] An order relation on a ·value space· is a mathematical relation that imposes a ·total order· or a ·partial order· on the members of the ·value space·.

[Definition:] A ·value space·, and hence a datatype, is said to be ordered if there exists an ·order-relation· defined for that ·value space·.

[Definition:] A partial order is an ·order-relation· that is irreflexive, asymmetric and transitive.

A ·partial order· has the following properties:

for no a in the ·value space·, a < a (irreflexivity)
for all a and b in the ·value space·, a < b implies not(b < a) (asymmetry)
for all a, b and c in the ·value space·, a < b and b < c implies a < c (transitivity)

The notation a <> b is used to indicate the case when a != b and neither a < b nor b < a. For any values a and b from different ·primitive· ·value space·s, a <> b.

[Definition:] When a <> b, a and b are incomparable,[Definition:] otherwise they are comparable.

[Definition:] A total order is an ·partial order· such that for no a and b is it the case that a <> b.

A ·total order· has all of the properties specified above for ·partial order·, plus the following property:

for all a and b in the ·value space·, either a < b or b < a or a = b

Note: The fact that this specification does not define an ·order-relation · for some datatype does not mean that some other application cannot treat that datatype as being ordered by imposing its own order relation.

·ordered· provides for:

indicating whether an ·order-relation· is defined on a ·value space·, and if so, whether that ·order-relation· is a ·partial order· or a ·total order·

4.2.2.1 The ordered Schema Component

Schema Component : ordered

{value}: One of {false, partial, total}.

{value} depends on {variety}, {facets} and {member type definitions} in the Simple Type Definition component in which a ·ordered· component appears as a member of {fundamental facets}.

When {variety} is ·atomic·, {value} is inherited from {value} of {base type definition}. For all ·primitive· types {value} is as specified in the table in Fundamental Facets (§C.1).

When {variety} is ·list·, {value} is false.

When {variety} is ·union·, {value} is partial unless one of the following:

If every member of {member type definitions} is derived from a common ancestor other than the simple ur-type, then {value} is the same as that ancestor's ordered facet
If every member of {member type definitions} has a {value} of false for the ordered facet, then {value} is false

4.2.3 bounded

[Definition:] A value u in an ·ordered· ·value space· U is said to be an inclusive upper bound of a ·value space· V (where V is a subset of U) if for all v in V, u >= v.

[Definition:] A value u in an ·ordered· ·value space· U is said to be an exclusive upper bound of a ·value space· V (where V is a subset of U) if for all v in V, u > v.

[Definition:] A value l in an ·ordered· ·value space· L is said to be an inclusive lower bound of a ·value space· V (where V is a subset of L) if for all v in V, l <= v.

[Definition:] A value l in an ·ordered· ·value space· L is said to be an exclusive lower bound of a ·value space· V (where V is a subset of L) if for all v in V, l < v.

[Definition:] A datatype is bounded if its ·value space· has either an ·inclusive upper bound· or an ·exclusive upper bound· and either an ·inclusive lower bound· or an ·exclusive lower bound·.

·bounded· provides for:

indicating whether a ·value space· is ·bounded·

4.2.3.1 The bounded Schema Component

Schema Component : bounded

{value}: A boolean.

{value} depends on {variety}, {facets} and {member type definitions} in the Simple Type Definition component in which a ·bounded· component appears as a member of {fundamental facets}.

When {variety} is ·atomic·, if one of ·minInclusive· or ·minExclusive· and one of ·maxInclusive· or ·maxExclusive· are among {facets} , then {value} is true; else {value} is false.

When {variety} is ·list·, if ·length· or both of ·minLength· and ·maxLength· are among {facets}, then {value} is true; else {value} is false.

When {variety} is ·union·, if {value} is true for every member of {member type definitions} and all members of {member type definitions} share a common ancestor, then {value} is true; else {value} is false.

4.2.4 cardinality

[Definition:] Every ·value space· has associated with it the concept of cardinality. Some ·value space·s are finite, some are countably infinite while still others could conceivably be uncountably infinite (although no ·value space· defined by this specification is uncountable infinite). A datatype is said to have the cardinality of its ·value space·.

It is sometimes useful to categorize ·value space·s (and hence, datatypes) as to their cardinality. There are two significant cases:

·value space·s that are finite
·value space·s that are countably infinite

·cardinality· provides for:

indicating whether the ·cardinality· of a ·value space· is finite or countably infinite

4.2.4.1 The cardinality Schema Component

Schema Component : cardinality

{value}: One of {finite, countably infinite}.

{value} depends on {variety}, {facets} and {member type definitions} in the Simple Type Definition component in which a ·cardinality· component appears as a member of {fundamental facets}.

When {variety} is ·atomic· and {value} of {base type definition} is finite, then {value} is finite.

When {variety} is ·atomic· and {value} of {base type definition} is countably infinite and either of the following conditions are true, then {value} is finite; else {value} is countably infinite:

one of ·length·, ·maxLength·, ·totalDigits· is among {facets},
all of the following are true:
1. one of ·minInclusive· or ·minExclusive· is among {facets}
2. one of ·maxInclusive· or ·maxExclusive· is among {facets}
3. either of the following are true:
  1. ·fractionDigits· is among {facets}
  2. {base type definition} is one of date, gYearMonth, gYear, gMonthDay, gDay or gMonth or any type ·derived· from them

When {variety} is ·list·, if ·length· or both of ·minLength· and ·maxLength· are among {facets}, then {value} is finite; else {value} is countably infinite.

When {variety} is ·union·, if {value} is finite for every member of {member type definitions}, then {value} is finite; else {value} is countably infinite.

4.2.5 numeric

[Definition:] A datatype is said to be numeric if its values are conceptually quantities (in some mathematical number system).

[Definition:] A datatype whose values are not ·numeric· is said to be non-numeric.

·numeric· provides for:

indicating whether a ·value space· is ·numeric·

4.2.5.1 The numeric Schema Component

Schema Component : numeric

{value}: A boolean

{value} depends on {variety}, {facets}, {base type definition} and {member type definitions} in the Simple Type Definition component in which a ·cardinality· component appears as a member of {fundamental facets}.

When {variety} is ·atomic·, {value} is inherited from {value} of {base type definition}. For all ·primitive· types {value} is as specified in the table in Fundamental Facets (§C.1).

When {variety} is ·list·, {value} is false.

When {variety} is ·union·, if {value} is true for every member of {member type definitions}, then {value} is true; else {value} is false.

4.3 Constraining Facets

        4.3.1 length
        4.3.2 minLength
        4.3.3 maxLength
        4.3.4 pattern
        4.3.5 enumeration
        4.3.6 whiteSpace
        4.3.7 maxInclusive
        4.3.8 maxExclusive
        4.3.9 minExclusive
        4.3.10 minInclusive
        4.3.11 totalDigits
        4.3.12 fractionDigits

4.3.1 length

[Definition:] length is the number of units of length, where units of length varies depending on the type that is being ·derived· from. The value of length ·must· be a nonNegativeInteger.

For string and datatypes ·derived· from string, length is measured in units of characters as defined in [XML 1.0 (Second Edition)]. For anyURI, length is measured in units of characters (as for string). For hexBinary and base64Binary and datatypes ·derived· from them, length is measured in octets (8 bits) of binary data. For datatypes ·derived· by ·list·, length is measured in number of list items.

Note: For string and datatypes ·derived · from string, length will not always coincide with "string length" as perceived by some users or with the number of storage units in some digital representation. Therefore, care should be taken when specifying a value for length and in attempting to infer storage requirements from a given value for length.

·length· provides for:

Constraining a ·value space· to values with a specific number of units of length, where units of length varies depending on {base type definition}.

Example

The following is the definition of a ·user-derived · datatype to represent product codes which must be exactly 8 characters in length. By fixing the value of the length facet we ensure that types derived from productCode can change or set the values of other facets, such as pattern, but cannot change the length.

4.3.1.1 The length Schema Component

Schema Component : length

{value}: A nonNegativeInteger.
{fixed}: A boolean.
{annotation}: Optional. An annotation.

If {fixed} is true, then types for which the current type is the {base type definition} cannot specify a value for length other than {value}.

4.3.1.2 XML Representation of length Schema Components

The XML representation for a length schema component is a element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation Summary: length Element Information Item

  fixed = boolean : false
  id = ID
  value = nonNegativeInteger
  {any attributes with non-schema namespace . . .}>
  Content: (annotation?)

length Schema Component

Property	Representation
{value}	The actual value of the `value` [attribute]
{fixed}	The actual value of the `fixed` [attribute], if present, otherwise false
{annotation}	The annotations corresponding to all the element information items in the [children], if any.

4.3.1.3 length Validation Rules

Validation Rule: Length Valid

A value in a ·value space · is facet-valid with respect to ·length ·, determined as follows:

1 if the {variety} is ·atomic · then

1.1 if {primitive type definition} is string or anyURI, then the length of the value, as measured in characters ·must · be equal to {value};

1.2 if {primitive type definition} is hexBinary or base64Binary, then the length of the value, as measured in octets of the binary data, ·must · be equal to {value};

1.3 if {primitive type definition} is QName or NOTATION, then any {value} is facet-valid.

2 if the {variety} is ·list ·, then the length of the value, as measured in list items, ·must · be equal to {value}

The use of ·length· on datatypes ·derived· from QName and NOTATION is deprecated. Future versions of this specification may remove this facet for these datatypes.

4.3.1.4 Constraints on length Schema Components

Schema Component Constraint: length and minLength or maxLength

If length is a member of {facets} then

1 It is an error for minLength to be a member of {facets} unless

1.1 the {value} of minLength <= the {value} of length and

1.2 there is type definition from which this one is derived by one or more restriction steps in which minLength has the same {value} and length is not specified.

2 It is an error for maxLength to be a member of {facets} unless

2.1 the {value} of length <= the {value} of maxLength and

2.2 there is type definition from which this one is derived by one or more restriction steps in which maxLength has the same {value} and length is not specified.

Schema Component Constraint: length valid restriction

It is an ·error · if length is among the members of {facets} of {base type definition} and {value} is not equal to the {value} of the parent length.

4.3.2 minLength

[Definition:] minLength is the minimum number of units of length, where units of length varies depending on the type that is being ·derived· from. The value of minLength ·must· be a nonNegativeInteger.

For string and datatypes ·derived· from string, minLength is measured in units of characters as defined in [XML 1.0 (Second Edition)]. For hexBinary and base64Binary and datatypes ·derived· from them, minLength is measured in octets (8 bits) of binary data. For datatypes ·derived· by ·list·, minLength is measured in number of list items.

Note: For string and datatypes ·derived · from string, minLength will not always coincide with "string length" as perceived by some users or with the number of storage units in some digital representation. Therefore, care should be taken when specifying a value for minLength and in attempting to infer storage requirements from a given value for minLength.

·minLength· provides for:

Constraining a ·value space· to values with at least a specific number of units of length, where units of length varies depending on {base type definition}.

Example

The following is the definition of a ·user-derived · datatype which requires strings to have at least one character (i.e., the empty string is not in the ·value space · of this datatype).

4.3.2.1 The minLength Schema Component

Schema Component : minLength

{value}: A nonNegativeInteger.
{fixed}: A boolean.
{annotation}: Optional. An annotation.

If {fixed} is true, then types for which the current type is the {base type definition} cannot specify a value for minLength other than {value}.

4.3.2.2 XML Representation of minLength Schema Component

The XML representation for a minLength schema component is a element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation Summary: minLength Element Information Item

  fixed = boolean : false
  id = ID
  value = nonNegativeInteger
  {any attributes with non-schema namespace . . .}>
  Content: (annotation?)

minLength Schema Component

Property	Representation
{value}	The actual value of the `value` [attribute]
{fixed}	The actual value of the `fixed` [attribute], if present, otherwise false
{annotation}	The annotations corresponding to all the element information items in the [children], if any.

4.3.2.3 minLength Validation Rules

Validation Rule: minLength Valid

A value in a ·value space · is facet-valid with respect to ·minLength ·, determined as follows:

1 if the {variety} is ·atomic · then

1.1 if {primitive type definition} is string or anyURI, then the length of the value, as measured in characters ·must · be greater than or equal to {value};

1.2 if {primitive type definition} is hexBinary or base64Binary, then the length of the value, as measured in octets of the binary data, ·must · be greater than or equal to {value};

1.3 if {primitive type definition} is QName or NOTATION, then any {value} is facet-valid.

2 if the {variety} is ·list ·, then the length of the value, as measured in list items, ·must · be greater than or equal to {value}

The use of ·minLength· on datatypes ·derived· from QName and NOTATION is deprecated. Future versions of this specification may remove this facet for these datatypes.

4.3.2.4 Constraints on minLength Schema Components

Schema Component Constraint: minLength <= maxLength

If both minLength and maxLength are members of {facets}, then the {value} of minLength ·must · be less than or equal to the {value} of maxLength.

Schema Component Constraint: minLength valid restriction

It is an ·error · if minLength is among the members of {facets} of {base type definition} and {value} is less than the {value} of the parent minLength.

4.3.3 maxLength

[Definition:] maxLength is the maximum number of units of length, where units of length varies depending on the type that is being ·derived· from. The value of maxLength ·must· be a nonNegativeInteger.

For string and datatypes ·derived· from string, maxLength is measured in units of characters as defined in [XML 1.0 (Second Edition)]. For hexBinary and base64Binary and datatypes ·derived· from them, maxLength is measured in octets (8 bits) of binary data. For datatypes ·derived· by ·list·, maxLength is measured in number of list items.

Note: For string and datatypes ·derived · from string, maxLength will not always coincide with "string length" as perceived by some users or with the number of storage units in some digital representation. Therefore, care should be taken when specifying a value for maxLength and in attempting to infer storage requirements from a given value for maxLength.

·maxLength· provides for:

Constraining a ·value space· to values with at most a specific number of units of length, where units of length varies depending on {base type definition}.

Example

The following is the definition of a ·user-derived · datatype which might be used to accept form input with an upper limit to the number of characters that are acceptable.

4.3.3.1 The maxLength Schema Component

Schema Component : maxLength

{value}: A nonNegativeInteger.
{fixed}: A boolean.
{annotation}: Optional. An annotation.

If {fixed} is true, then types for which the current type is the {base type definition} cannot specify a value for maxLength other than {value}.

4.3.3.2 XML Representation of maxLength Schema Components

The XML representation for a maxLength schema component is a element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation Summary: maxLength Element Information Item

  fixed = boolean : false
  id = ID
  value = nonNegativeInteger
  {any attributes with non-schema namespace . . .}>
  Content: (annotation?)

maxLength Schema Component

Property	Representation
{value}	The actual value of the `value` [attribute]
{fixed}	The actual value of the `fixed` [attribute], if present, otherwise false
{annotation}	The annotations corresponding to all the element information items in the [children], if any.

4.3.3.3 maxLength Validation Rules

Validation Rule: maxLength Valid

A value in a ·value space · is facet-valid with respect to ·maxLength ·, determined as follows:

1 if the {variety} is ·atomic · then

1.1 if {primitive type definition} is string or anyURI, then the length of the value, as measured in characters ·must · be less than or equal to {value};

1.2 if {primitive type definition} is hexBinary or base64Binary, then the length of the value, as measured in octets of the binary data, ·must · be less than or equal to {value};

1.3 if {primitive type definition} is QName or NOTATION, then any {value} is facet-valid.

2 if the {variety} is ·list ·, then the length of the value, as measured in list items, ·must · be less than or equal to {value}

The use of ·maxLength· on datatypes ·derived· from QName and NOTATION is deprecated. Future versions of this specification may remove this facet for these datatypes.

4.3.3.4 Constraints on maxLength Schema Components

Schema Component Constraint: maxLength valid restriction

It is an ·error · if maxLength is among the members of {facets} of {base type definition} and {value} is greater than the {value} of the parent maxLength.

4.3.4 pattern

[Definition:] pattern is a constraint on the ·value space· of a datatype which is achieved by constraining the ·lexical space· to literals which match a specific pattern. The value of pattern ·must· be a ·regular expression·.

·pattern· provides for:

Constraining a ·value space· to values that are denoted by literals which match a specific ·regular expression·.

Example

The following is the definition of a ·user-derived · datatype which is a better representation of postal codes in the United States, by limiting strings to those which are matched by a specific ·regular expression ·.

4.3.4.1 The pattern Schema Component

Schema Component : pattern

{value}: A ·regular expression ·.
{annotation}: Optional. An annotation.

4.3.4.2 XML Representation of pattern Schema Components

The XML representation for a pattern schema component is a element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation Summary: pattern Element Information Item

  id = ID
  value = string
  {any attributes with non-schema namespace . . .}>
  Content: (annotation?)

{value} ·must · be a valid ·regular expression ·.

pattern Schema Component

Property	Representation
{value}	The actual value of the `value` [attribute]
{annotation}	The annotations corresponding to all the element information items in the [children], if any.

4.3.4.3 Constraints on XML Representation of pattern

Schema Representation Constraint: Multiple patterns

If multiple element information items appear as [children] of a , the [value]s should be combined as if they appeared in a single ·regular expression · as separate ·branch ·es.

Note: It is a consequence of the schema representation constraint Multiple patterns (§4.3.4.3) and of the rules for ·restriction · that ·pattern · facets specified on the same step in a type derivation are ORed together, while ·pattern · facets specified on different steps of a type derivation are ANDed together.

Thus, to impose two ·pattern· constraints simultaneously, schema authors may either write a single ·pattern· which expresses the intersection of the two ·pattern·s they wish to impose, or define each ·pattern· on a separate type derivation step.

4.3.4.4 pattern Validation Rules

Validation Rule: pattern valid

A literal in a ·lexical space · is facet-valid with respect to ·pattern · if:

1 the literal is among the set of character sequences denoted by the ·regular expression · specified in {value}.

4.3.5 enumeration

[Definition:] enumeration constrains the ·value space· to a specified set of values.

enumeration does not impose an order relation on the ·value space· it creates; the value of the ·ordered· property of the ·derived· datatype remains that of the datatype from which it is ·derived·.

·enumeration· provides for:

Constraining a ·value space· to a specified set of values.

Example

The following example is a datatype definition for a ·user-derived · datatype which limits the values of dates to the three US holidays enumerated. This datatype definition would appear in a schema authored by an "end-user" and shows how to define a datatype by enumerating the values in its ·value space ·. The enumerated values must be type-valid literals for the ·base type ·.


    
        some US holidays
    
    
      
        
            New Year's day
        
      
      
        
            4th of July
        
      
      
        
            Christmas

4.3.5.1 The enumeration Schema Component

Schema Component : enumeration

{value}: A set of values from the ·value space · of the {base type definition}.
{annotation}: Optional. An annotation.

4.3.5.2 XML Representation of enumeration Schema Components

The XML representation for an enumeration schema component is an element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation Summary: enumeration Element Information Item

  id = ID
  value = anySimpleType
  {any attributes with non-schema namespace . . .}>
  Content: (annotation?)

{value} ·must · be in the ·value space · of {base type definition}.

enumeration Schema Component

Property	Representation
{value}	The actual value of the `value` [attribute]
{annotation}	The annotations corresponding to all the element information items in the [children], if any.

4.3.5.3 Constraints on XML Representation of enumeration

Schema Representation Constraint: Multiple enumerations

If multiple element information items appear as [children] of a the {value} of the enumeration component should be the set of all such [value]s.

4.3.5.4 enumeration Validation Rules

Validation Rule: enumeration valid

A value in a ·value space · is facet-valid with respect to ·enumeration · if the value is one of the values specified in {value}

4.3.5.5 Constraints on enumeration Schema Components

Schema Component Constraint: enumeration valid restriction

It is an ·error · if any member of {value} is not in the ·value space · of {base type definition}.

4.3.6 whiteSpace

[Definition:] whiteSpace constrains the ·value space· of types ·derived· from string such that the various behaviors specified in Attribute Value Normalization in [XML 1.0 (Second Edition)] are realized. The value of whiteSpace must be one of {preserve, replace, collapse}.

preserve: No normalization is done, the value is not changed (this is the behavior required by [XML 1.0 (Second Edition)] for element content)
replace: All occurrences of #x9 (tab), #xA (line feed) and #xD (carriage return) are replaced with #x20 (space)
collapse: After the processing implied by replace, contiguous sequences of #x20's are collapsed to a single #x20, and leading and trailing #x20's are removed.

Note: The notation #xA used here (and elsewhere in this specification) represents the Universal Character Set (UCS) code point hexadecimal A (line feed), which is denoted by U+000A. This notation is to be distinguished from

, which is the XML character reference to that same UCS code point.

whiteSpace is applicable to all ·atomic· and ·list· datatypes. For all ·atomic· datatypes other than string (and types ·derived· by ·restriction· from it) the value of whiteSpace is collapse and cannot be changed by a schema author; for string the value of whiteSpace is preserve; for any type ·derived· by ·restriction· from string the value of whiteSpace can be any of the three legal values. For all datatypes ·derived· by ·list· the value of whiteSpace is collapse and cannot be changed by a schema author. For all datatypes ·derived· by ·union· whiteSpace does not apply directly; however, the normalization behavior of ·union· types is controlled by the value of whiteSpace on that one of the ·memberTypes· against which the ·union· is successfully validated.

Note: For more information on whiteSpace, see the discussion on white space normalization in Schema Component Details in [XML Schema Part 1: Structures].

·whiteSpace· provides for:

Constraining a ·value space· according to the white space normalization rules.

Example

The following example is the datatype definition for the token ·built-in · ·derived · datatype.

4.3.6.1 The whiteSpace Schema Component

Schema Component : whiteSpace

{value}: One of {preserve, replace, collapse}.
{fixed}: A boolean.
{annotation}: Optional. An annotation.

If {fixed} is true, then types for which the current type is the {base type definition} cannot specify a value for whiteSpace other than {value}.

4.3.6.2 XML Representation of whiteSpace Schema Components

The XML representation for a whiteSpace schema component is a element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation Summary: whiteSpace Element Information Item

  fixed = boolean : false
  id = ID
  value = (collapse | preserve | replace)
  {any attributes with non-schema namespace . . .}>
  Content: (annotation?)

whiteSpace Schema Component

Property	Representation
{value}	The actual value of the `value` [attribute]
{fixed}	The actual value of the `fixed` [attribute], if present, otherwise false
{annotation}	The annotations corresponding to all the element information items in the [children], if any.

4.3.6.3 whiteSpace Validation Rules

Note: There are no ·Validation Rule ·s associated ·whiteSpace ·. For more information, see the discussion on white space normalization in Schema Component Details in [XML Schema Part 1: Structures].

4.3.6.4 Constraints on whiteSpace Schema Components

Schema Component Constraint: whiteSpace valid restriction

It is an ·error · if whiteSpace is among the members of {facets} of {base type definition} and any of the following conditions is true:

1 {value} is replace or preserve and the {value} of the parent whiteSpace is collapse

2 {value} is preserve and the {value} of the parent whiteSpace is replace

4.3.7 maxInclusive

[Definition:] maxInclusive is the ·inclusive upper bound· of the ·value space· for a datatype with the ·ordered· property. The value of maxInclusive ·must· be in the ·value space· of the ·base type·.

·maxInclusive· provides for:

Constraining a ·value space· to values with a specific ·inclusive upper bound·.

Example

The following is the definition of a ·user-derived · datatype which limits values to integers less than or equal to 100, using ·maxInclusive ·.

4.3.7.1 The maxInclusive Schema Component

Schema Component : maxInclusive

{value}: A value from the ·value space · of the {base type definition}.
{fixed}: A boolean.
{annotation}: Optional. An annotation.

If {fixed} is true, then types for which the current type is the {base type definition} cannot specify a value for maxInclusive other than {value}.

4.3.7.2 XML Representation of maxInclusive Schema Components

The XML representation for a maxInclusive schema component is a element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation Summary: maxInclusive Element Information Item

  fixed = boolean : false
  id = ID
  value = anySimpleType
  {any attributes with non-schema namespace . . .}>
  Content: (annotation?)

{value} ·must · be in the ·value space · of {base type definition}.

maxInclusive Schema Component

Property	Representation
{value}	The actual value of the `value` [attribute]
{fixed}	The actual value of the `fixed` [attribute], if present, otherwise false, if present, otherwise false
{annotation}	The annotations corresponding to all the element information items in the [children], if any.

4.3.7.3 maxInclusive Validation Rules

Validation Rule: maxInclusive Valid

A value in an ·ordered · ·value space · is facet-valid with respect to ·maxInclusive ·, determined as follows:

1 if the ·numeric · property in {fundamental facets} is true, then the value ·must · be numerically less than or equal to {value};

2 if the ·numeric · property in {fundamental facets} is false (i.e., {base type definition} is one of the date and time related datatypes), then the value ·must · be chronologically less than or equal to {value};

4.3.7.4 Constraints on maxInclusive Schema Components

Schema Component Constraint: minInclusive <= maxInclusive

It is an ·error · for the value specified for ·minInclusive · to be greater than the value specified for ·maxInclusive · for the same datatype.

Schema Component Constraint: maxInclusive valid restriction

It is an ·error · if any of the following conditions is true:

1 maxInclusive is among the members of {facets} of {base type definition} and {value} is greater than the {value} of the parent maxInclusive

2 maxExclusive is among the members of {facets} of {base type definition} and {value} is greater than or equal to the {value} of the parent maxExclusive

3 minInclusive is among the members of {facets} of {base type definition} and {value} is less than the {value} of the parent minInclusive

4 minExclusive is among the members of {facets} of {base type definition} and {value} is less than or equal to the {value} of the parent minExclusive

4.3.8 maxExclusive

[Definition:] maxExclusive is the ·exclusive upper bound· of the ·value space· for a datatype with the ·ordered· property. The value of maxExclusive ·must· be in the ·value space· of the ·base type· or be equal to {value} in {base type definition}.

·maxExclusive· provides for:

Constraining a ·value space· to values with a specific ·exclusive upper bound·.

Example

The following is the definition of a ·user-derived · datatype which limits values to integers less than or equal to 100, using ·maxExclusive ·.

Note that the ·value space · of this datatype is identical to the previous one (named 'one-hundred-or-less').

4.3.8.1 The maxExclusive Schema Component

Schema Component : maxExclusive

{value}: A value from the ·value space · of the {base type definition}.
{fixed}: A boolean.
{annotation}: Optional. An annotation.

If {fixed} is true, then types for which the current type is the {base type definition} cannot specify a value for maxExclusive other than {value}.

4.3.8.2 XML Representation of maxExclusive Schema Components

The XML representation for a maxExclusive schema component is a element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation Summary: maxExclusive Element Information Item

  fixed = boolean : false
  id = ID
  value = anySimpleType
  {any attributes with non-schema namespace . . .}>
  Content: (annotation?)

{value} ·must · be in the ·value space · of {base type definition}.

maxExclusive Schema Component

Property	Representation
{value}	The actual value of the `value` [attribute]
{fixed}	The actual value of the `fixed` [attribute], if present, otherwise false
{annotation}	The annotations corresponding to all the element information items in the [children], if any.

4.3.8.3 maxExclusive Validation Rules

Validation Rule: maxExclusive Valid

A value in an ·ordered · ·value space · is facet-valid with respect to ·maxExclusive ·, determined as follows:

1 if the ·numeric · property in {fundamental facets} is true, then the value ·must · be numerically less than {value};

4.3.8.4 Constraints on maxExclusive Schema Components

Schema Component Constraint: maxInclusive and maxExclusive

It is an ·error · for both ·maxInclusive · and ·maxExclusive · to be specified in the same derivation step of a datatype definition.

Schema Component Constraint: minExclusive <= maxExclusive

It is an ·error · for the value specified for ·minExclusive · to be greater than the value specified for ·maxExclusive · for the same datatype.

Schema Component Constraint: maxExclusive valid restriction

It is an ·error · if any of the following conditions is true:

1 maxExclusive is among the members of {facets} of {base type definition} and {value} is greater than the {value} of the parent maxExclusive

2 maxInclusive is among the members of {facets} of {base type definition} and {value} is greater than the {value} of the parent maxInclusive

3 minInclusive is among the members of {facets} of {base type definition} and {value} is less than or equal to the {value} of the parent minInclusive

4 minExclusive is among the members of {facets} of {base type definition} and {value} is less than or equal to the {value} of the parent minExclusive

4.3.9 minExclusive

[Definition:] minExclusive is the ·exclusive lower bound· of the ·value space· for a datatype with the ·ordered· property. The value of minExclusive ·must· be in the ·value space· of the ·base type· or be equal to {value} in {base type definition}.

·minExclusive· provides for:

Constraining a ·value space· to values with a specific ·exclusive lower bound·.

Example

The following is the definition of a ·user-derived · datatype which limits values to integers greater than or equal to 100, using ·minExclusive ·.

Note that the ·value space · of this datatype is identical to the previous one (named 'one-hundred-or-more').

4.3.9.1 The minExclusive Schema Component

Schema Component : minExclusive

{value}: A value from the ·value space · of the {base type definition}.
{fixed}: A boolean.
{annotation}: Optional. An annotation.

If {fixed} is true, then types for which the current type is the {base type definition} cannot specify a value for minExclusive other than {value}.

4.3.9.2 XML Representation of minExclusive Schema Components

The XML representation for a minExclusive schema component is a element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation Summary: minExclusive Element Information Item

  fixed = boolean : false
  id = ID
  value = anySimpleType
  {any attributes with non-schema namespace . . .}>
  Content: (annotation?)

{value} ·must · be in the ·value space · of {base type definition}.

minExclusive Schema Component

Property	Representation
{value}	The actual value of the `value` [attribute]
{fixed}	The actual value of the `fixed` [attribute], if present, otherwise false
{annotation}	The annotations corresponding to all the element information items in the [children], if any.

4.3.9.3 minExclusive Validation Rules

Validation Rule: minExclusive Valid

A value in an ·ordered · ·value space · is facet-valid with respect to ·minExclusive · if:

1 if the ·numeric · property in {fundamental facets} is true, then the value ·must · be numerically greater than {value};

4.3.9.4 Constraints on minExclusive Schema Components

Schema Component Constraint: minInclusive and minExclusive

It is an ·error · for both ·minInclusive · and ·minExclusive · to be specified for the same datatype.

Schema Component Constraint: minExclusive < maxInclusive

It is an ·error · for the value specified for ·minExclusive · to be greater than or equal to the value specified for ·maxInclusive · for the same datatype.

Schema Component Constraint: minExclusive valid restriction

It is an ·error · if any of the following conditions is true:

1 minExclusive is among the members of {facets} of {base type definition} and {value} is less than the {value} of the parent minExclusive

2 maxInclusive is among the members of {facets} of {base type definition} and {value} is greater the {value} of the parent maxInclusive

3 minInclusive is among the members of {facets} of {base type definition} and {value} is less than the {value} of the parent minInclusive

4 maxExclusive is among the members of {facets} of {base type definition} and {value} is greater than or equal to the {value} of the parent maxExclusive

4.3.10 minInclusive

[Definition:] minInclusive is the ·inclusive lower bound· of the ·value space· for a datatype with the ·ordered· property. The value of minInclusive ·must· be in the ·value space· of the ·base type·.

·minInclusive· provides for:

Constraining a ·value space· to values with a specific ·inclusive lower bound·.

Example

The following is the definition of a ·user-derived · datatype which limits values to integers greater than or equal to 100, using ·minInclusive ·.

4.3.10.1 The minInclusive Schema Component

Schema Component : minInclusive

{value}: A value from the ·value space · of the {base type definition}.
{fixed}: A boolean.
{annotation}: Optional. An annotation.

If {fixed} is true, then types for which the current type is the {base type definition} cannot specify a value for minInclusive other than {value}.

4.3.10.2 XML Representation of minInclusive Schema Components

The XML representation for a minInclusive schema component is a element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation Summary: minInclusive Element Information Item

  fixed = boolean : false
  id = ID
  value = anySimpleType
  {any attributes with non-schema namespace . . .}>
  Content: (annotation?)

{value} ·must · be in the ·value space · of {base type definition}.

minInclusive Schema Component

Property	Representation
{value}	The actual value of the `value` [attribute]
{fixed}	The actual value of the `fixed` [attribute], if present, otherwise false
{annotation}	The annotations corresponding to all the element information items in the [children], if any.

4.3.10.3 minInclusive Validation Rules

Validation Rule: minInclusive Valid

A value in an ·ordered · ·value space · is facet-valid with respect to ·minInclusive · if:

1 if the ·numeric · property in {fundamental facets} is true, then the value ·must · be numerically greater than or equal to {value};

4.3.10.4 Constraints on minInclusive Schema Components

Schema Component Constraint: minInclusive < maxExclusive

It is an ·error · for the value specified for ·minInclusive · to be greater than or equal to the value specified for ·maxExclusive · for the same datatype.

Schema Component Constraint: minInclusive valid restriction

It is an ·error · if any of the following conditions is true:

1 minInclusive is among the members of {facets} of {base type definition} and {value} is less than the {value} of the parent minInclusive

2 maxInclusive is among the members of {facets} of {base type definition} and {value} is greater the {value} of the parent maxInclusive

3 minExclusive is among the members of {facets} of {base type definition} and {value} is less than or equal to the {value} of the parent minExclusive

4 maxExclusive is among the members of {facets} of {base type definition} and {value} is greater than or equal to the {value} of the parent maxExclusive

4.3.11 totalDigits

[Definition:] totalDigits controls the maximum number of values in the ·value space· of datatypes ·derived· from decimal, by restricting it to numbers that are expressible as i × 10^-n where i and n are integers such that |i| < 10^totalDigits and 0 <= n <= totalDigits. The value of totalDigits ·must· be a positiveInteger.

The term totalDigits is chosen to reflect the fact that it restricts the ·value space· to those values that can be represented lexically using at most totalDigits digits. Note that it does not restrict the ·lexical space· directly; a lexical representation that adds additional leading zero digits or trailing fractional zero digits is still permitted.

4.3.11.1 The totalDigits Schema Component

Schema Component : totalDigits

{value}: A positiveInteger.
{fixed}: A boolean.
{annotation}: Optional. An annotation.

If {fixed} is true, then types for which the current type is the {base type definition} cannot specify a value for totalDigits other than {value}.

4.3.11.2 XML Representation of totalDigits Schema Components

The XML representation for a totalDigits schema component is a element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation Summary: totalDigits Element Information Item

  fixed = boolean : false
  id = ID
  value = positiveInteger
  {any attributes with non-schema namespace . . .}>
  Content: (annotation?)

totalDigits Schema Component

Property	Representation
{value}	The actual value of the `value` [attribute]
{fixed}	The actual value of the `fixed` [attribute], if present, otherwise false
{annotation}	The annotations corresponding to all the element information items in the [children], if any.

4.3.11.3 totalDigits Validation Rules

Validation Rule: totalDigits Valid

A value in a ·value space · is facet-valid with respect to ·totalDigits · if:

1 that value is expressible as i × 10^-n where i and n are integers such that |i| < 10^{value} and 0 <= n <= {value}.

4.3.11.4 Constraints on totalDigits Schema Components

Schema Component Constraint: totalDigits valid restriction

It is an ·error · if totalDigits is among the members of {facets} of {base type definition} and {value} is greater than the {value} of the parent totalDigits

4.3.12 fractionDigits

[Definition:] fractionDigits controls the size of the minimum difference between values in the ·value space· of datatypes ·derived· from decimal, by restricting the ·value space· to numbers that are expressible as i × 10^-n where i and n are integers and 0 <= n <= fractionDigits. The value of fractionDigits ·must· be a nonNegativeInteger.

The term fractionDigits is chosen to reflect the fact that it restricts the ·value space· to those values that can be represented lexically using at most fractionDigits to the right of the decimal point. Note that it does not restrict the ·lexical space· directly; a non-·canonical lexical representation· that adds additional leading zero digits or trailing fractional zero digits is still permitted.

Example

The following is the definition of a ·user-derived · datatype which could be used to represent the magnitude of a person's body temperature on the Celsius scale. This definition would appear in a schema authored by an "end-user" and shows how to define a datatype by specifying facet values which constrain the range of the ·base type ·.

4.3.12.1 The fractionDigits Schema Component

Schema Component : fractionDigits

{value}: A nonNegativeInteger.
{fixed}: A boolean.
{annotation}: Optional. An annotation.

If {fixed} is true, then types for which the current type is the {base type definition} cannot specify a value for fractionDigits other than {value}.

4.3.12.2 XML Representation of fractionDigits Schema Components

The XML representation for a fractionDigits schema component is a element information item. The correspondences between the properties of the information item and properties of the component are as follows:

XML Representation Summary: fractionDigits Element Information Item

  fixed = boolean : false
  id = ID
  value = nonNegativeInteger
  {any attributes with non-schema namespace . . .}>
  Content: (annotation?)

fractionDigits Schema Component

Property	Representation
{value}	The actual value of the `value` [attribute]
{fixed}	The actual value of the `fixed` [attribute], if present, otherwise false
{annotation}	The annotations corresponding to all the element information items in the [children], if any.

4.3.12.3 fractionDigits Validation Rules

Validation Rule: fractionDigits Valid

A value in a ·value space · is facet-valid with respect to ·fractionDigits · if:

1 that value is expressible as i × 10^-n where i and n are integers and 0 <= n <= {value}.

4.3.12.4 Constraints on fractionDigits Schema Components

Schema Component Constraint: fractionDigits less than or equal to totalDigits

It is an ·error · for ·fractionDigits · to be greater than ·totalDigits ·.

Schema Component Constraint: fractionDigits valid restriction

It is an ·error · if ·fractionDigits · is among the members of {facets} of {base type definition} and {value} is greater than the {value} of the parent ·fractionDigits ·.

5 Conformance

This specification describes two levels of conformance for datatype processors. The first is required of all processors. Support for the other will depend on the application environments for which the processor is intended.

[Definition:] Minimally conforming processors ·must· completely and correctly implement the ·Constraint on Schemas· and ·Validation Rule· .

[Definition:] Processors which accept schemas in the form of XML documents as described in XML Representation of Simple Type Definition Schema Components (§4.1.2) (and other relevant portions of Datatype components (§4)) are additionally said to provide conformance to the XML Representation of Schemas, and ·must·, when processing schema documents, completely and correctly implement all ·Schema Representation Constraint·s in this specification, and ·must· adhere exactly to the specifications in XML Representation of Simple Type Definition Schema Components (§4.1.2) (and other relevant portions of Datatype components (§4)) for mapping the contents of such documents to schema components for use in validation.

Note: By separating the conformance requirements relating to the concrete syntax of XML schema documents, this specification admits processors which validate using schemas stored in optimized binary representations, dynamically created schemas represented as programming language data structures, or implementations in which particular schemas are compiled into executable code such as C or Java. Such processors can be said to be ·minimally conforming · but not necessarily in ·conformance to the XML Representation of Schemas ·.

A Schema for Datatype Definitions (normative)


        

        
        

        
        

        
        
        
        
        
        
        
        
        
        
        
        
        
        
        
        
        ]>



  
    
      The schema corresponding to this document is normative,
      with respect to the syntactic constraints it expresses in the
      XML Schema language.  The documentation (within <documentation>
      elements) below, is not normative, but rather highlights important
      aspects of the W3C Recommendation of which this is a part
    
  
  
    
      First the built-in primitive datatypes.  These definitions are for
      information only, the real built-in definitions are magic.
    
    
      For each built-in datatype in this schema (both primitive and
      derived) can be uniquely addressed via a URI constructed
      as follows:
        1) the base URI is the URI of the XML Schema namespace
        2) the fragment identifier is the name of the datatype

      For example, to address the int datatype, the URI is:

        http://www.w3.org/2001/XMLSchema#int

      Additionally, each facet definition element can be uniquely
      addressed via a URI constructed as follows:
        1) the base URI is the URI of the XML Schema namespace
        2) the fragment identifier is the name of the facet

      For example, to address the maxInclusive facet, the URI is:

        http://www.w3.org/2001/XMLSchema#maxInclusive

      Additionally, each facet usage in a built-in datatype definition
      can be uniquely addressed via a URI constructed as follows:
        1) the base URI is the URI of the XML Schema namespace
        2) the fragment identifier is the name of the datatype, followed
           by a period (".") followed by the name of the facet

      For example, to address the usage of the maxInclusive facet in
      the definition of int, the URI is:

        http://www.w3.org/2001/XMLSchema#int.maxInclusive

    
  
  
    
      
        
        
        
        
        
        
        
        
        
        
      
      
    
    
      
    
  
  
    
      
        
        
        
        
        
        
      
      
    
    
      
    
  
  
    
      
        
        
        
        
        
        
        
        
        
        
        
      
      
    
    
      
    
  
  
    
      
        
        
        
        
        
        
        
        
        
        
        
      
      
    
    
      
    
  
  
    
      
        
        
        
        
        
        
        
        
        
        
        
        
        
      
      
    
    
      
    
  
  
    
      
        
        
        
        
        
        
        
        
        
        
        
      
      
    
    
      
    
  
  
    
      
        
        
        
        
        
        
        
        
        
        
        
      
      
    
    
      
    
  
  
    
      
        
        
        
        
        
        
        
        
        
        
        
      
      
    
    
      
    
  
  
    
      
        
        
        
        
        
        
        
        
        
        
        
      
      
    
    
      
    
  
  
    
      
        
        
        
        
        
        
        
        
        
        
        
      
      
    
    
      
    
  
  
    
      
        
        
        
        
        
        
        
        
        
        
        
      
      
    
    
      
    
  
  
    
      
        
        
        
        
        
        
        
        
        
        
        
      
      
    
    
      
    
  
  
    
      
        
        
        
        
        
        
        
        
        
        
        
      
      
    
    
      
    
  
  
    
      
        
        
        
        
        
        
        
        
        
        
        
      
      
    
    
      
    
  
  
    
      
        
        
        
        
        
        
        
        
        
        
      
      
    
    
      
    
  
  
    
      
        
        
        
        
        
        
        
        
        
        
      
      
    
    
      
    
  
  
    
      
        
        
        
        
        
        
        
        
        
        
      
      
    
    
      
    
  
  
    
      
        
        
        
        
        
        
        
        
        
        
      
      
    
    
      
    
  
  
    
      
        
        
        
        
        
        
        
        
        
        
      
      
      
        NOTATION cannot be used directly in a schema; rather a type
        must be derived from it by specifying at least one enumeration
        facet whose value is the name of a NOTATION declared in the
        schema.
      
    
    
      
    
  
  
    
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            pattern specifies the content of section 2.12 of XML 1.0e2
            and RFC 3066 (Revised version of RFC 1766).
          
        
      
    
  
  
    
      
        
        
        
        
        
        
        
        
        
        
      
      
    
    
      
        
      
      
    
  
  
    
      
        
        
        
        
        
        
        
        
        
        
      
      
    
    
      
        
      
      
    
  
  
    
      
    
    
      
        
          
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   A utility type, not for public use
    
    
      
      
      
      
      
    
  
  
    
      
      
      
    
  
  
    
      
   #all or (possibly empty) subset of {restriction, union, list}
   
      
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       We should use a substitution group for facets, but
       that's ruled out because it would allow users to
       add their own, which we're not ready for yet.
    
    
    
      
      
      
      
      
      
      
      
      
      
      
      
    
  
  
    
      
      
    
  
  
    
      
        
          base attribute and simpleType child are mutually
          exclusive, but one or other is required
        
      
      
        
          
          
        
      
    
  
  
    
      
        
          itemType attribute and simpleType child are mutually
          exclusive, but one or other is required
        
      
      
        
          
            
          
          
        
      
    
  
  
    
      
        
          memberTypes attribute must be non-empty or there must be
          at least one simpleType child

B DTD for Datatype Definitions (non-normative)

C Datatypes and Facets

C.1 Fundamental Facets

The following table shows the values of the fundamental facets for each ·built-in· datatype.

	Datatype	ordered	bounded	cardinality	numeric
primitive	string	false	false	countably infinite	false
	boolean	false	false	finite	false
	float	partial	true	finite	true
	double	partial	true	finite	true
	decimal	total	false	countably infinite	true
	duration	partial	false	countably infinite	false
	dateTime	partial	false	countably infinite	false
	time	partial	false	countably infinite	false
	date	partial	false	countably infinite	false
	gYearMonth	partial	false	countably infinite	false
	gYear	partial	false	countably infinite	false
	gMonthDay	partial	false	countably infinite	false
	gDay	partial	false	countably infinite	false
	gMonth	partial	false	countably infinite	false
	hexBinary	false	false	countably infinite	false
	base64Binary	false	false	countably infinite	false
	anyURI	false	false	countably infinite	false
	QName	false	false	countably infinite	false
	NOTATION	false	false	countably infinite	false

derived	normalizedString	false	false	countably infinite	false
	token	false	false	countably infinite	false
	language	false	false	countably infinite	false
	IDREFS	false	false	countably infinite	false
	ENTITIES	false	false	countably infinite	false
	NMTOKEN	false	false	countably infinite	false
	NMTOKENS	false	false	countably infinite	false
	Name	false	false	countably infinite	false
	NCName	false	false	countably infinite	false
	ID	false	false	countably infinite	false
	IDREF	false	false	countably infinite	false
	ENTITY	false	false	countably infinite	false
	integer	total	false	countably infinite	true
	nonPositiveInteger	total	false	countably infinite	true
	negativeInteger	total	false	countably infinite	true
	long	total	true	finite	true
	int	total	true	finite	true
	short	total	true	finite	true
	byte	total	true	finite	true
	nonNegativeInteger	total	false	countably infinite	true
	unsignedLong	total	true	finite	true
	unsignedInt	total	true	finite	true
	unsignedShort	total	true	finite	true
	unsignedByte	total	true	finite	true
	positiveInteger	total	false	countably infinite	true

D ISO 8601 Date and Time Formats

D.1 ISO 8601 Conventions

The ·primitive· datatypes duration, dateTime, time, date, gYearMonth, gMonthDay, gDay, gMonth and gYear use lexical formats inspired by [ISO 8601]. Following [ISO 8601], the lexical forms of these datatypes can include only the characters #20 through #7F. This appendix provides more detail on the ISO formats and discusses some deviations from them for the datatypes defined in this specification.

[ISO 8601] "specifies the representation of dates in the proleptic Gregorian calendar and times and representations of periods of time". The proleptic Gregorian calendar includes dates prior to 1582 (the year it came into use as an ecclesiastical calendar). It should be pointed out that the datatypes described in this specification do not cover all the types of data covered by [ISO 8601], nor do they support all the lexical representations for those types of data.

[ISO 8601] lexical formats are described using "pictures" in which characters are used in place of decimal digits. The allowed decimal digits are (#x30-#x39). For the primitive datatypes dateTime, time, date, gYearMonth, gMonthDay, gDay, gMonth and gYear. these characters have the following meanings:

C -- represents a digit used in the thousands and hundreds components, the "century" component, of the time element "year". Legal values are from 0 to 9.
Y -- represents a digit used in the tens and units components of the time element "year". Legal values are from 0 to 9.
M -- represents a digit used in the time element "month". The two digits in a MM format can have values from 1 to 12.
D -- represents a digit used in the time element "day". The two digits in a DD format can have values from 1 to 28 if the month value equals 2, 1 to 29 if the month value equals 2 and the year is a leap year, 1 to 30 if the month value equals 4, 6, 9 or 11, and 1 to 31 if the month value equals 1, 3, 5, 7, 8, 10 or 12.
h -- represents a digit used in the time element "hour". The two digits in a hh format can have values from 0 to 24. If the value of the hour element is 24 then the values of the minutes element and the seconds element must be 00 and 00.
m -- represents a digit used in the time element "minute". The two digits in a mm format can have values from 0 to 59.
s -- represents a digit used in the time element "second". The two digits in a ss format can have values from 0 to 60. In the formats described in this specification the whole number of seconds ·may· be followed by decimal seconds to an arbitrary level of precision. This is represented in the picture by "ss.sss". A value of 60 or more is allowed only in the case of leap seconds.
Strictly speaking, a value of 60 or more is not sensible unless the month and day could represent March 31, June 30, September 30, or December 31 in UTC. Because the leap second is added or subtracted as the last second of the day in UTC time, the long (or short) minute could occur at other times in local time. In cases where the leap second is used with an inappropriate month and day it, and any fractional seconds, should considered as added or subtracted from the following minute.

For all the information items indicated by the above characters, leading zeros are required where indicated.

In addition to the above, certain characters are used as designators and appear as themselves in lexical formats.

T -- is used as time designator to indicate the start of the representation of the time of day in dateTime.
Z -- is used as time-zone designator, immediately (without a space) following a data element expressing the time of day in Coordinated Universal Time (UTC) in dateTime, time, date, gYearMonth, gMonthDay, gDay, gMonth, and gYear.

In the lexical format for duration the following characters are also used as designators and appear as themselves in lexical formats:

P -- is used as the time duration designator, preceding a data element representing a given duration of time.
Y -- follows the number of years in a time duration.
M -- follows the number of months or minutes in a time duration.
D -- follows the number of days in a time duration.
H -- follows the number of hours in a time duration.
S -- follows the number of seconds in a time duration.

The values of the Year, Month, Day, Hour and Minutes components are not restricted but allow an arbitrary integer. Similarly, the value of the Seconds component allows an arbitrary decimal. Thus, the lexical format for duration and datatypes derived from it does not follow the alternative format of § 5.5.3.2.1 of [ISO 8601].

D.2 Truncated and Reduced Formats

[ISO 8601] supports a variety of "truncated" formats in which some of the characters on the left of specific formats, for example, the century, can be omitted. Truncated formats are, in general, not permitted for the datatypes defined in this specification with three exceptions. The time datatype uses a truncated format for dateTime which represents an instant of time that recurs every day. Similarly, the gMonthDay and gDay datatypes use left-truncated formats for date. The datatype gMonth uses a right and left truncated format for date.

[ISO 8601] also supports a variety of "reduced" or right-truncated formats in which some of the characters to the right of specific formats, such as the time specification, can be omitted. Right truncated formats are also, in general, not permitted for the datatypes defined in this specification with the following exceptions: right-truncated representations of dateTime are used as lexical representations for date, gMonth, gYear.

D.3 Deviations from ISO 8601 Formats

        D.3.1 Sign Allowed
        D.3.2 No Year Zero
        D.3.3 More Than 9999 Years
        D.3.4 Time zone permitted

D.3.1 Sign Allowed

An optional minus sign is allowed immediately preceding, without a space, the lexical representations for duration, dateTime, date, gYearMonth, gYear.

D.3.2 No Year Zero

The year "0000" is an illegal year value.

D.3.3 More Than 9999 Years

To accommodate year values greater than 9999, more than four digits are allowed in the year representations of dateTime, date, gYearMonth, and gYear. This follows [ISO 8601:2000 Second Edition].

D.3.4 Time zone permitted

The lexical representations for the datatypes date, gYearMonth, gMonthDay, gDay, gMonth and gYear permit an optional trailing time zone specificiation.

E Adding durations to dateTimes

Given a dateTime S and a duration D, this appendix specifies how to compute a dateTime E where E is the end of the time period with start S and duration D i.e. E = S + D. Such computations are used, for example, to determine whether a dateTime is within a specific time period. This appendix also addresses the addition of durations to the datatypes date, gYearMonth, gYear, gDay and gMonth, which can be viewed as a set of dateTimes. In such cases, the addition is made to the first or starting dateTime in the set.

This is a logical explanation of the process. Actual implementations are free to optimize as long as they produce the same results. The calculation uses the notation S[year] to represent the year field of S, S[month] to represent the month field, and so on. It also depends on the following functions:

fQuotient(a, b) = the greatest integer less than or equal to a/b
- fQuotient(-1,3) = -1
- fQuotient(0,3)...fQuotient(2,3) = 0
- fQuotient(3,3) = 1
- fQuotient(3.123,3) = 1
modulo(a, b) = a - fQuotient(a,b)*b
- modulo(-1,3) = 2
- modulo(0,3)...modulo(2,3) = 0...2
- modulo(3,3) = 0
- modulo(3.123,3) = 0.123
fQuotient(a, low, high) = fQuotient(a - low, high - low)
- fQuotient(0, 1, 13) = -1
- fQuotient(1, 1, 13) ... fQuotient(12, 1, 13) = 0
- fQuotient(13, 1, 13) = 1
- fQuotient(13.123, 1, 13) = 1
modulo(a, low, high) = modulo(a - low, high - low) + low
- modulo(0, 1, 13) = 12
- modulo(1, 1, 13) ... modulo(12, 1, 13) = 1...12
- modulo(13, 1, 13) = 1
- modulo(13.123, 1, 13) = 1.123
maximumDayInMonthFor(yearValue, monthValue) =
- M := modulo(monthValue, 1, 13)
- Y := yearValue + fQuotient(monthValue, 1, 13)
- Return a value based on M and Y:

31	M = January, March, May, July, August, October, or December
30	M = April, June, September, or November
29	M = February AND (modulo(Y, 400) = 0 OR (modulo(Y, 100) != 0) AND modulo(Y, 4) = 0)
28	Otherwise

E.1 Algorithm

Essentially, this calculation is equivalent to separating D into and fields. The is added to S. If the day is out of range, it is pinned to be within range. Thus April 31 turns into April 30. Then the is added. This latter addition can cause the year and month to change.

Leap seconds are handled by the computation by treating them as overflows. Essentially, a value of 60 seconds in S is treated as if it were a duration of 60 seconds added to S (with a zero seconds field). All calculations thereafter use 60 seconds per minute.

Thus the addition of either PT1M or PT60S to any dateTime will always produce the same result. This is a special definition of addition which is designed to match common practice, and -- most importantly -- be stable over time.

A definition that attempted to take leap-seconds into account would need to be constantly updated, and could not predict the results of future implementation's additions. The decision to introduce a leap second in UTC is the responsibility of the [International Earth Rotation Service (IERS)]. They make periodic announcements as to when leap seconds are to be added, but this is not known more than a year in advance. For more information on leap seconds, see [U.S. Naval Observatory Time Service Department].

The following is the precise specification. These steps must be followed in the same order. If a field in D is not specified, it is treated as if it were zero. If a field in S is not specified, it is treated in the calculation as if it were the minimum allowed value in that field, however, after the calculation is concluded, the corresponding field in E is removed (set to unspecified).

Months (may be modified additionally below)
- temp := S[month] + D[month]
- E[month] := modulo(temp, 1, 13)
- carry := fQuotient(temp, 1, 13)
Years (may be modified additionally below)
- E[year] := S[year] + D[year] + carry
Zone
- E[zone] := S[zone]
Seconds
- temp := S[second] + D[second]
- E[second] := modulo(temp, 60)
- carry := fQuotient(temp, 60)
Minutes
- temp := S[minute] + D[minute] + carry
- E[minute] := modulo(temp, 60)
- carry := fQuotient(temp, 60)
Hours
- temp := S[hour] + D[hour] + carry
- E[hour] := modulo(temp, 24)
- carry := fQuotient(temp, 24)
Days
- if S[day] > maximumDayInMonthFor(E[year], E[month])
  - tempDays := maximumDayInMonthFor(E[year], E[month])
- else if S[day] < 1
  - tempDays := 1
- else
  - tempDays := S[day]
- E[day] := tempDays + D[day] + carry
- START LOOP
  - IF E[day] < 1
    - E[day] := E[day] + maximumDayInMonthFor(E[year], E[month] - 1)
    - carry := -1
  - ELSE IF E[day] > maximumDayInMonthFor(E[year], E[month])
    - E[day] := E[day] - maximumDayInMonthFor(E[year], E[month])
    - carry := 1
  - ELSE EXIT LOOP
  - temp := E[month] + carry
  - E[month] := modulo(temp, 1, 13)
  - E[year] := E[year] + fQuotient(temp, 1, 13)
  - GOTO START LOOP

Examples:

dateTime	duration	result
2000-01-12T12:13:14Z	P1Y3M5DT7H10M3.3S	2001-04-17T19:23:17.3Z
2000-01	-P3M	1999-10
2000-01-12	PT33H	2000-01-13

E.2 Commutativity and Associativity

Time durations are added by simply adding each of their fields, respectively, without overflow.

The order of addition of durations to instants is significant. For example, there are cases where:

((dateTime + duration1) + duration2) != ((dateTime + duration2) + duration1)

Example:

(2000-03-30 + P1D) + P1M = 2000-03-31 + P1M = 2000-04-30

(2000-03-30 + P1M) + P1D = 2000-04-30 + P1D = 2000-05-01

F Regular Expressions

A ·regular expression· R is a sequence of characters that denote a set of strings L(R). When used to constrain a ·lexical space·, a regular expression R asserts that only strings in L(R) are valid literals for values of that type.

Note: Unlike some popular regular expression languages (including those defined by Perl and standard Unix utilities), the regular expression language defined here implicitly anchors all regular expressions at the head and tail, as the most common use of regular expressions in ·pattern · is to match entire literals. For example, a datatype ·derived · from string such that all values must begin with the character A (#x41) and end with the character Z (#x5a) would be defined as follows:

In regular expression languages that are not implicitly anchored at the head and tail, it is customary to write the equivalent regular expression as:

^A.*Z$

where "^" anchors the pattern at the head and "$" anchors at the tail.

In those rare cases where an unanchored match is desired, including .* at the beginning and ending of the regular expression will achieve the desired results. For example, a datatype ·derived· from string such that all values must contain at least 3 consecutive A (#x41) characters somewhere within the value could be defined as follows:

[Definition:] A regular expression is composed from zero or more ·branch·es, separated by | characters.

Regular Expression

[1] regExp ::= branch ( '|' branch )*

For all ·branch·es S, and for all ·regular expression·s T, valid ·regular expression·s R are:	Denoting the set of strings L(R) containing:
(empty string)	the set containing just the empty string
S	all strings in L(S)
S\|T	all strings in L(S) and all strings in L(T)

[Definition:] A branch consists of zero or more ·piece·s, concatenated together.

Branch

[2] branch ::= piece*

For all ·piece·s S, and for all ·branch·es T, valid ·branch·es R are:	Denoting the set of strings L(R) containing:
S	all strings in L(S)
ST	all strings st with s in L(S) and t in L(T)

[Definition:] A piece is an ·atom·, possibly followed by a ·quantifier·.

Piece

[3] piece ::= atom quantifier?

For all ·atom·s S and non-negative integers n, m such that n <= m, valid ·piece·s R are:	Denoting the set of strings L(R) containing:
S	all strings in L(S)
S?	the empty string, and all strings in L(S).
S*	All strings in L(S?) and all strings st with s in L(S)* and t in L(S). ( all concatenations of zero or more strings from L(S) )
S+	All strings st with s in L(S) and t in L(S). ( all concatenations of one or more strings from L(S) )*
S{n,m}	All strings st with s in L(S) and t in L(S{n-1,m-1}). ( All sequences of at least n, and at most m, strings from L(S) )
S{n}	All strings in L(S{n,n}). ( All sequences of exactly n strings from L(S) )
S{n,}	All strings in L(S{n}S) ( All sequences of at least n, strings from L(S) )*
S{0,m}	All strings st with s in L(S?) and t in L(S{0,m-1}). ( All sequences of at most m, strings from L(S) )
S{0,0}	The set containing only the empty string

Note: The regular expression language in the Perl Programming Language [Perl] does not include a quantifier of the form S{,m}, since it is logically equivalent to S{0,m}. We have, therefore, left this logical possibility out of the regular expression language defined by this specification.

[Definition:] A quantifier is one of ?, *, +, {n,m} or {n,}, which have the meanings defined in the table above.

Quanitifer

[4]	`quantifier`	::=	`[?*+] \| ( '{' quantity '}' )`
[5]	`quantity`	::=	`quantRange \| quantMin \| QuantExact`
[6]	`quantRange`	::=	`QuantExact ',' QuantExact`
[7]	`quantMin`	::=	`QuantExact ','`
[8]	`QuantExact`	::=	`[0-9]+`

[Definition:] An atom is either a ·normal character·, a ·character class·, or a parenthesized ·regular expression·.

Atom

[9] atom ::= Char | charClass | ( '(' regExp ')' )

For all ·normal character·s c, ·character class·es C, and ·regular expression·s S, valid ·atom·s R are:	Denoting the set of strings L(R) containing:
c	the single string consisting only of c
C	all strings in L(C)
(S)	all strings in L(S)

[Definition:] A metacharacter is either ., /, ?, *, +, {, } (, ), [ or ]. These characters have special meanings in ·regular expression·s, but can be escaped to form ·atom·s that denote the sets of strings containing only themselves, i.e., an escaped ·metacharacter· behaves like a ·normal character·.

[Definition:] A normal character is any XML character that is not a metacharacter. In ·regular expression·s, a normal character is an atom that denotes the singleton set of strings containing only itself.

Normal Character

[10] Char ::= [^./?*+()|#x5B#x5D]

Note that a ·normal character· can be represented either as itself, or with a character reference.

F.1 Character Classes

[Definition:] A character class is an ·atom· R that identifies a set of characters C(R). The set of strings L(R) denoted by a character class R contains one single-character string "c" for each character c in C(R).

Character Class

[11] charClass ::= charClassEsc | charClassExpr | WildcardEsc

A character class is either a ·character class escape· or a ·character class expression·.

[Definition:] A character class expression is a ·character group· surrounded by [ and ] characters. For all character groups G, [G] is a valid character class expression, identifying the set of characters C([G]) = C(G).

Character Class Expression

[12] charClassExpr ::= '[' charGroup ']'

[Definition:] A character group is either a ·positive character group·, a ·negative character group·, or a ·character class subtraction·.

Character Group

[13] charGroup ::= posCharGroup | negCharGroup | charClassSub

[Definition:] A positive character group consists of one or more ·character range·s or ·character class escape·s, concatenated together. A positive character group identifies the set of characters containing all of the characters in all of the sets identified by its constituent ranges or escapes.

Positive Character Group

[14] posCharGroup ::= ( charRange | charClassEsc )+

For all ·character range·s R, all ·character class escape·s E, and all ·positive character group·s P, valid ·positive character group·s G are:	Identifying the set of characters C(G) containing:
R	all characters in C(R).
E	all characters in C(E).
RP	all characters in C(R) and all characters in C(P).
EP	all characters in C(E) and all characters in C(P).

[Definition:] A negative character group is a ·positive character group· preceded by the ^ character. For all ·positive character group·s P, ^P is a valid negative character group, and C(^P) contains all XML characters that are not in C(P).

Negative Character Group

[15] negCharGroup ::= '^' posCharGroup

[Definition:] A character class subtraction is a ·character class expression· subtracted from a ·positive character group· or ·negative character group·, using the - character.

Character Class Subtraction

[16] charClassSub ::= ( posCharGroup | negCharGroup ) '-' charClassExpr

For any ·positive character group· or ·negative character group· G, and any ·character class expression· C, G-C is a valid ·character class subtraction·, identifying the set of all characters in C(G) that are not also in C(C).

[Definition:] A character range R identifies a set of characters C(R) containing all XML characters with UCS code points in a specified range.

Character Range

[17]	`charRange`	::=	`seRange \| XmlCharIncDash`
[18]	`seRange`	::=	`charOrEsc '-' charOrEsc`
[20]	`charOrEsc`	::=	`XmlChar \| SingleCharEsc`
[21]	`XmlChar`	::=	`[^/#x2D#x5B#x5D]`
[22]	`XmlCharIncDash`	::=	`[^/#x5B#x5D]`

A single XML character is a ·character range· that identifies the set of characters containing only itself. All XML characters are valid character ranges, except as follows:

The [, ], - and / characters are not valid character ranges;
The ^ character is only valid at the beginning of a ·positive character group· if it is part of a ·negative character group·
The - character is a valid character range only at the beginning or end of a ·positive character group·.

Note: The grammar for ·character range · as given above is ambiguous, but the second and third bullets above together remove the ambiguity.

A ·character range· ·may· also be written in the form s-e, identifying the set that contains all XML characters with UCS code points greater than or equal to the code point of s, but not greater than the code point of e.

s-e is a valid character range iff:

s is a ·single character escape·, or an XML character;
s is not /
If s is the first character in a ·character class expression·, then s is not ^
e is a ·single character escape·, or an XML character;
e is not / or [; and
The code point of e is greater than or equal to the code point of s;

Note: The code point of a ·single character escape · is the code point of the single character in the set of characters that it identifies.

F.1.1 Character Class Escapes

[Definition:] A character class escape is a short sequence of characters that identifies predefined character class. The valid character class escapes are the ·single character escape·s, the ·multi-character escape·s, and the ·category escape·s (including the ·block escape·s).

Character Class Escape

[23] charClassEsc ::= ( SingleCharEsc | MultiCharEsc | catEsc | complEsc )

[Definition:] A single character escape identifies a set containing a only one character -- usually because that character is difficult or impossible to write directly into a ·regular expression·.

Single Character Escape

[24] SingleCharEsc ::= '/' [nrt/|.?*+(){}#x2D#x5B#x5D#x5E]

The valid ·single character escape·s are:	Identifying the set of characters C(R) containing:
`/n`	the newline character (#xA)
`/r`	the return character (#xD)
`/t`	the tab character (#x9)
`//`	/
`/\|`	\|
`/.`	.
`/-`	-
`/^`	^
`/?`	?
`/*`	*
`/+`	+
`/{`	{
`/}`	}
`/(`	(
`/)`	)
`/[`	[
`/]`	]

[Definition:] [Unicode Database] specifies a number of possible values for the "General Category" property and provides mappings from code points to specific character properties. The set containing all characters that have property X, can be identified with a category escape /p{X}. The complement of this set is specified with the category escape /P{X}. ([/P{X}] = [^/p{X}]).

Category Escape

[25]	`catEsc`	::=	`'/p{' charProp '}'`
[26]	`complEsc`	::=	`'/P{' charProp '}'`
[27]	`charProp`	::=	`IsCategory \| IsBlock`

Note: [Unicode Database] is subject to future revision. For example, the mapping from code points to character properties might be updated. All ·minimally conforming · processors ·must · support the character properties defined in the version of [Unicode Database] that is current at the time this specification became a W3C Recommendation. However, implementors are encouraged to support the character properties defined in any future version.

The following table specifies the recognized values of the "General Category" property.

Category	Property	Meaning
Letters	L	All Letters
	Lu	uppercase
	Ll	lowercase
	Lt	titlecase
	Lm	modifier
	Lo	other

Marks	M	All Marks
	Mn	nonspacing
	Mc	spacing combining
	Me	enclosing

Numbers	N	All Numbers
	Nd	decimal digit
	Nl	letter
	No	other

Punctuation	P	All Punctuation
	Pc	connector
	Pd	dash
	Ps	open
	Pe	close
	Pi	initial quote (may behave like Ps or Pe depending on usage)
	Pf	final quote (may behave like Ps or Pe depending on usage)
	Po	other

Separators	Z	All Separators
	Zs	space
	Zl	line
	Zp	paragraph

Symbols	S	All Symbols
	Sm	math
	Sc	currency
	Sk	modifier
	So	other

Other	C	All Others
	Cc	control
	Cf	format
	Co	private use
	Cn	not assigned

Categories

[28]	`IsCategory`	::=	`Letters \| Marks \| Numbers \| Punctuation \| Separators \| Symbols \| Others`
[29]	`Letters`	::=	`'L' [ultmo]?`
[30]	`Marks`	::=	`'M' [nce]?`
[31]	`Numbers`	::=	`'N' [dlo]?`
[32]	`Punctuation`	::=	`'P' [cdseifo]?`
[33]	`Separators`	::=	`'Z' [slp]?`
[34]	`Symbols`	::=	`'S' [mcko]?`
[35]	`Others`	::=	`'C' [cfon]?`

Note: The properties mentioned above exclude the Cs property. The Cs property identifies "surrogate" characters, which do not occur at the level of the "character abstraction" that XML instance documents operate on.

[Definition:] [Unicode Database] groups code points into a number of blocks such as Basic Latin (i.e., ASCII), Latin-1 Supplement, Hangul Jamo, CJK Compatibility, etc. The set containing all characters that have block name X (with all white space stripped out), can be identified with a block escape /p{IsX}. The complement of this set is specified with the block escape /P{IsX}. ([/P{IsX}] = [^/p{IsX}]).

Block Escape

[36] IsBlock ::= 'Is' [a-zA-Z0-9#x2D]+

The following table specifies the recognized block names (for more information, see the "Blocks.txt" file in [Unicode Database]).

Start Code	End Code	Block Name	Start Code	End Code	Block Name
#x0000	#x007F	BasicLatin	#x0080	#x00FF	Latin-1Supplement
#x0100	#x017F	LatinExtended-A	#x0180	#x024F	LatinExtended-B
#x0250	#x02AF	IPAExtensions	#x02B0	#x02FF	SpacingModifierLetters
#x0300	#x036F	CombiningDiacriticalMarks	#x0370	#x03FF	Greek
#x0400	#x04FF	Cyrillic	#x0530	#x058F	Armenian
#x0590	#x05FF	Hebrew	#x0600	#x06FF	Arabic
#x0700	#x074F	Syriac	#x0780	#x07BF	Thaana
#x0900	#x097F	Devanagari	#x0980	#x09FF	Bengali
#x0A00	#x0A7F	Gurmukhi	#x0A80	#x0AFF	Gujarati
#x0B00	#

XML Schema Part 2: Datatypes Second Edition

XML Schema Part 2: Datatypes Second Edition

W3C Recommendation 28 October 2004

Abstract

Status of this Document

Table of Contents

Appendices

1 Introduction

1.1 Purpose

1.2 Requirements

1.3 Scope

1.4 Terminology

1.5 Constraints and Contributions

2 Type System

2.1 Datatype

2.2 Value space

2.3 Lexical space

2.3.1 Canonical Lexical Representation

2.4 Facets

2.4.1 Fundamental facets

2.4.2 Constraining or Non-fundamental facets

2.5 Datatype dichotomies

2.5.1 Atomic vs. list vs. union datatypes

2.5.1.1 Atomic datatypes

2.5.1.2 List datatypes

2.5.1.3 Union datatypes

2.5.2 Primitive vs. derived datatypes

2.5.2.1 Derived by restriction

2.5.2.2 Derived by list

2.5.2.3 Derived by union

2.5.3 Built-in vs. user-derived datatypes

3 Built-in datatypes

3.1 Namespace considerations

3.2 Primitive datatypes

3.2.1 string

3.2.1.1 Constraining facets

3.2.1.2 Derived datatypes

3.2.2 boolean

3.2.2.1 Lexical representation

3.2.2.2 Canonical representation

3.2.2.3 Constraining facets

3.2.3 decimal

3.2.3.1 Lexical representation

3.2.3.2 Canonical representation

3.2.3.3 Constraining facets

3.2.3.4 Derived datatypes

3.2.4 float

3.2.4.1 Lexical representation

3.2.4.2 Canonical representation

3.2.4.3 Constraining facets

3.2.5 double

3.2.5.1 Lexical representation

3.2.5.2 Canonical representation

3.2.5.3 Constraining facets

3.2.6 duration

3.2.6.1 Lexical representation

3.2.6.2 Order relation on duration

3.2.6.3 Facet Comparison for durations

3.2.6.4 Totally ordered durations

3.2.6.5 Constraining facets

3.2.7 dateTime

3.2.7.1 Lexical representation

3.2.7.2 Canonical representation

3.2.7.3 Timezones

3.2.7.4 Order relation on dateTime

3.2.7.5 Totally ordered dateTimes

3.2.7.6 Constraining facets

3.2.8 time

3.2.8.1 Lexical representation

3.2.8.2 Canonical representation

3.2.8.3 Constraining facets

3.2.9 date

3.2.9.1 Lexical representation

3.2.9.2 Canonical representation

3.2.10 gYearMonth

3.2.10.1 Lexical representation

3.2.10.2 Constraining facets

3.2.11 gYear

3.2.11.1 Lexical representation

3.2.11.2 Constraining facets