XML Core - Basic

General Principles Define the purpose of XML:

• why the standard was created
• the intended applications of XML (data exchange, structured data representation)
• limitations of XML:
  • XML Syntax
  • XML Usage
  • Types of data that can and cannot be stored in XML

Vocabulary Be comfortable with XML terminology:

• start tag / end tag
• element, root element, empty element
• attribute
• document, standalone document
• processing instruction
• declaration instruction

Document Structure

• Describe an XML document using declaration instructions like

<?xml version="1.0" encoding="US-ASCII" standalone="yes" ?>

• Follow the basic rules of XML document structure:
  • The declaration instruction is optional
  • All documents must have a single root element

• Write processing instructions:

<?cmd arg="val" ?>

Elements

• Distinguish valid element names from invalid ones.
• Use the element syntax to define start and end tags (<test></test>).
• Use the short notation for empty elements (<myelement/>).

Attributes

• Distinguish valid attribute names from invalid ones.
• Add attributes to an element using the allowed delimiters (' as well as ").
• Realize that attributes must be unique within an element, and that they are unordered.

Well-Formedness Explain the meaning and purpose of each concept:

• Well-formedness is mandatory (if a document is not well-formed, it is not an XML document)
• Elements must be properly nested (not crossed: <a><b></a></b>)
• Proper usage of whitespace

Text

• Combine markup, text and whitespace within an XML document
• Classify XML content as
  • Markup
  • Character Data (CDATA), including CDATA sections (<![CDATA[ 4+5 < 5+5 ]]>)

Namespaces

• Avoid ambiguous element names using namespaces
• Declare a namespace using xmlns
• Override the default namespace using xmlns
• Understand the notion of a qualified (element) name.

Comments Add comments to an XML document:

• using the proper syntax
• in any valid location within the document

Entities

Explain the purpose of the built-in entities:

• < (<)
• > (>)
• & (&)
• ' (')
• " (")

Insert a unicode character using decimal or hexadecimal notation:

• Ӓ (decimal)
• ꯍ (hexadecimal)