3/15/22, 2:09 PM COMP9315 22T1 - Assignment 1
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Submission:
COMP9315 22T1 Assignment 1
Adding a PersonName Data Type to
PostgreSQL
DBMS Implementation
Last updated: Tuesday 22nd February 2:16pm
Most recent changes are shown in red ... older changes are shown in brown.
Aims
This assignment aims to give you
an understanding of how data is treated inside a DBMS
practice in adding a new base type to PostgreSQL
The goal is to implement a new data type for PostgreSQL, complete with input/output functions,
comparison operators, formatting functions, and the ability to build indexes on values of the type.
Summary
Friday 18 March, 9:00pm
before starting this assignment, it would be useful to complete Prac Work P04
0.04 marks off the ceiling mark for each hour late
This assignment contributes 15 marks toward your total mark for this course.
Webcms3 > Assignments > Ass1 Submission > Make Submission
or, on CSEmachines, give cs9315 ass1 pname.c pname.source
Make sure that you read this assignment specification carefully and completely before starting work
on the assignment.
Questions which indicate that you haven't done this will simply get the response "Please read the
spec".
We use the following names in the discussion below
PG_CODE ... the directory where your PostgreSQL source code is located (typically
/localstorage/YOU/postgresql-14.1/)
PG_HOME ... the directory where you have installed the PostgreSQL binaries (typically
/localstorage/YOU/pgsql/bin/)
PG_DATA ... the directory where you have placed PostgreSQL's data (typically
/localstorage/YOU/pgsql/data/)
PG_LOG ... the file where you send PostgreSQL's log output (typically
/localstorage/YOU/pgsql/data/log)
Introduction
PostgreSQL has an extensibility model which, among other things, provides a well-defined process
for adding new data types into a PostgreSQL server. This capability has led to the development by
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PostgreSQL users of a number of types (such as polygons) which have become part of the standard
distribution. It also means that PostgreSQL is the database of choice in research projects which aim
to push the boundaries of what kind of data a DBMS can manage.
In this assignment, we will be adding a new data type for dealing with people's names. "Hmmm", you
say, "but aren't they just text strings, typically implemented as two attributes, one for family name
and one for given names?". That may be true, but making names into a separate base data type
allows us to explore how we store and manipulate them.
One common way of writing names (e.g. used in UNSW student systems) is
Shepherd,John Andrew
Lin,Xuemin
Eilish,Billie
Martin, Eric Andre
Lakshminarasimhan,Venkateswaran Chandrasekara
Marshall-Martin, Sally Angela
Featherstone,Albert Basil Ernest George Harold Randolph William
i.e.
FamilyName,GivenNames
We give a more precise description of what text strings are valid PersonNames below.
Adding Data Types in PostgreSQL
The process for adding new base data types in PostgreSQL is described in the following sections of
the PostgreSQL documentation:
37.13 User-defined Types
37.10 C-Language Functions
37.14 User-defined Operators
SQL: CREATE TYPE
SQL: CREATE OPERATOR
SQL: CREATE OPERATOR CLASS
Section 37.13 uses an example of a complex number type, which you can use as a starting point for
defining your PersonName data type (see below). There are other examples of new data types under
the directories:
PG_CODE/contrib/chkpass/ ... an auto-encrypted password datatype
PG_CODE/contrib/citext/ ... a case-insensitive character string datatype
PG_CODE/contrib/seg/ ... a confidence-interval datatype
These may or may not give you some useful ideas on how to implement the PersonName data type.
For example, many of these data types are fixed-size, while PersonNames are variable-sized. A
potentially useful example of implementing variable-sized types can be found in:
PG_CODE/src/tutorial/funcs.c ... implementation of several data types
Setting Up
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You ought to start this assignment with a fresh copy of PostgreSQL, without any changes that you
might have made for the Prac exercises (unless these changes are trivial). Note that you only need
to configure, compile and install your PostgreSQL server once for this assignment. All subsequent
compilation takes place in the src/tutorial directory, and only requires modification of the files
there.
Once you have re-installed your PostgreSQL server, you should run the following commands:
$ cd PG_CODE/src/tutorial
$ cp complex.c pname.c
$ cp complex.source pname.source
Note the pname.* files will contain many references to complex; I do not want to see any remaining
occurences of the word complex in the files that you eventually submit. These files simply provide a
template in which you create your PersonName type.
Once you've made the pname.* files, you should also edit the Makefile in this directory and add the
green text to the following lines:
MODULES = complex funcs pname
DATA_built = advanced.sql basics.sql complex.sql funcs.sql syscat.sql pname.sql
The rest of the work for this assignment involves editing only the pname.c and pname.source files.
In order for the Makefile to work properly, you must use the identifier OBJWD in the pname.source
file to refer to the directory holding the compiled library. You should never modify directly the
pname.sql file produced by the Makefile. Place all of your C code in the pname.c file; do not
create any other *.c files.
Note that your submitted versions of pname.c and pname.source should not contain any references
to the complex type. Make sure that the documentation (comments in program) describes the code
that you wrote. Leaving the word complex anywhere in a pname.* file will cost 1 mark.
The Person Name Data Type
We wish to define a new base type PersonName to represent people's names, in the format
FamilyName,GivenNames. We also aim to define a useful set of operations on values of type
PersonName and wish to be able to create indexes on PersonName attributes. How you represent
PersonName values internally, and how you implement the functions to manipulate them internally, is
up to you. However, they must satisfy the requirements below.
Once implemented correctly, you should be able to use your PostgreSQL server to build the
following kind of SQL applications:
create table Students (
zid integer primary key,
name PersonName not null,
degree text,
-- etc. etc.
);
insert into Students(zid,name,degree) values
(9300035,'Shepherd, John Andrew', 'BSc(Computer Science)'),
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(5012345,'Smith, Stephen', 'BE(Hons)(Software Engineering)');
create index on Students using hash (name);
select a.zid, a.name, b.zid
from Students a join Students b on (a.name = b.name);
select family(name), given(name), show(name)
from Students;
select name,count(*)
from Students
group by name;
Having defined a hash-based file structure, we would expect that the queries would make use of it.
You can check this by adding the keyword EXPLAIN before the query, e.g.
db=# explain analyze select * from Students where name='Smith,John';
which should, once you have correctly implemented the data type and loaded sufficient data, show
that an index-based scan of the data is being used. Note that this will only be evident if you use a
large amount of data (e.g. one of the larger test data samples to be provided).
Person Name values
Valid PersonNames will have the above format with the following qualifications:
there may be a single space after the comma
there will be no people with just one name (e.g. no Prince, Jesus, Aristotle, etc.)
there will be no numbers (e.g. noGates, William 3rd)
there will be no titles (e.g. no Dr, Prof, Mr, Ms)
there will be no initials (e.g. no Shepherd,John A)
In other words, you can ignore the possibility of certain types of names while implementing your
input and output functions.
A more precise definition can be given using a BNF grammar:
PersonName ::= Family','Given | Family', 'Given
Family ::= NameList
Given ::= NameList
NameList ::= Name | Name' 'NameList
Name ::= Upper Letters
Letter ::= Upper | Lower | Punc
Letters ::= Letter | Letter Letters
Upper ::= 'A' | 'B' | ... | 'Z'
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Lower ::= 'a' | 'b' | ... | 'z'
Punc ::= '-' | "'"
You should not make any assumptions about the maximum length of a PersonName.
Under this syntax, the following are valid names:
Smith,John
Smith, John
O'Brien, Patrick Sean
Mahagedara Patabendige,Minosha Mitsuaki Senakasiri
I-Sun, Chen Wang
Clifton-Everest,Charles Edward
The following names are not valid in our system:
Jesus # no single-word names
Smith , Harold # space before the ","
Gates, William H., III # no initials, too many commas
A,B C # names must at least 2 letters
Smith, john # names begin with an upper-case letter
Think about why each of the above is invalid in terms of the syntax definition.
Important: for this assignment, we define an ordering on names as follows:
the ordering is determined initially by the ordering on the Family Name
if the Family Names are equal, then the ordering is determined by the Given Names
ordering of parts is determined lexically
There are examples of how this works in the section on Operations on PersonNames below.
Representing Person Names
The first thing you need to do is to decide on an internal representation for your PersonName data
type. You should do this, however, after you have looked at the description of the operators below,
since what they require may affect how you decide to structure your internal PersonName values.
When you read strings representing PersonName values, they are converted into your internal form,
stored in the database in this form, and operations on PersonName values are carried out using this
data structure. It is useful to define a canonical form for names, which may be slightly different to the
form in which they are read (e.g. "Smith, John" might be rendered as "Smith,John"). When you
display PersonName values, you should show them in canonical form, regardless of how they were
entered or how they are stored.
The first functions you need to write are ones to read and display values of type PersonName. You
should write analogues of the functions complex_in(), complex_out that are defined in the file
complex.c. Call them, e.g., pname_in() and pname_out(). Make sure that you use the V1 style
function interface (as is done in complex.c).
Note that the two input/output functions should be complementary, meaning that any string displayed
by the output function must be able to be read using the input function. There is no requirement for
you to retain the precise string that was used for input (e.g. you could store the PersonName value
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internally in a different form such as splitting it into two strings: one for the family name(s), and one
for the given name(s)).
One thing that pname_in() must do is determine whether the name has the correct structure
(according to the grammar above). Your pname_out() should display each name in a format that
can be read by pname_in().
Note that you are not required to define binary input/output functions, called receive_function and
send_function in the PostgreSQL documentation, and called complex_send and complex_recv in
the complex.cfile.
As noted above, you cannot assume anything about the maximum length of names. If your solution
uses two fixed-size buffers (one for family, one for given) then your mark is limited to 6/10.
Operations on person names
You must implement all of the following operations for the PersonName type:
PersonName = PersonName ... two names are equal
Two PersonNames are equivalent if, they have the same family name(s) and the same given
name(s).
PersonName : Smith,John
PersonName : Smith, John
PersonName : Smith, John David
PersonName : Smith, James
(PersonName = PersonName ) is true
(PersonName = PersonName ) is true
(PersonName = PersonName ) is true (commutative)
(PersonName = PersonName ) is false
(PersonName = PersonName ) is false
PersonName > PersonName ... the first PersonName is greater than the second
PersonName is greater than PersonName if the Family part of PersonName is lexically
greater than the Family part of PersonName . If the Family parts are equal, then PersonName
is greater than PersonName if the Given part of PersonName is lexically greater than the
Given part of PersonName .
PersonName : Smith,James
PersonName : Smith,John
PersonName : Smith,John David
PersonName : Zimmerman, Trent
(PersonName > PersonName ) is false
(PersonName > PersonName ) is false
(PersonName > PersonName ) is true
(PersonName > PersonName ) is false
(PersonName > PersonName ) is true
Other operations: <>, >=, <, <=
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You should also implement the above operations, whose semantics is hopefully obvious from
the descriptions above. The operators can typically be implemented quite simply in terms of the
first two operators.
family(PersonName) returns just the Family part of a name
PersonName : Smith,James
PersonName : O'Brien,Patrick Sean
PersonName : Mahagedara Patabendige,Minosha Mitsuaki Senakasir
PersonName : Clifton-Everest,David Ewan
family(PersonName ) returns "Smith"
family(PersonName ) returns "O'Brien"
family(PersonName ) returns "Mahagedara Patabendige"
family(PersonName ) returns "Clifton-Everest"
given(PersonName) returns just the Given part of a name
PersonName : Smith,James
PersonName : O'Brien,Patrick Sean
PersonName : Mahagedara Patabendige,Minosha Mitsuaki Senakasir
PersonName : Clifton-Everest,David Ewan
given(PersonName ) returns "James"
given(PersonName ) returns "Patrick Sean"
given(PersonName ) returns "Minosha Mitsuaki Senakasir"
given(PersonName ) returns "David Ewan"
show(PersonName) returns a displayable version of the name
It appends the entire Family name to the first Given name (everything before the first space, if
any), separated by a single space.
PersonName : Smith,James
PersonName : O'Brien,Patrick Sean
PersonName : Mahagedara Patabendige,Minosha Mitsuaki Senakasir
PersonName : Clifton-Everest,David Ewan
PersonName : Bronte,Greta-Anna Maryanne
show(PersonName ) returns "James Smith"
show(PersonName ) returns "Patrick O'Brien"
show(PersonName ) returns "Minosha Mahagedara Patabendige"
show(PersonName ) returns "David Clifton-Everest"
show(PersonName ) returns "Greta-Anna Bronte"
Hint: test out as many of your C functions as you can outside PostgreSQL (e.g. write a simple test
driver) before you try to install them in PostgreSQL. This will make debugging much easier.
You should ensure that your definitions capture the full semantics of the operators (e.g. specify
commutativity if the operator is commutative). You should also ensure that you provide sufficient
definitions so that users of the PersonName type can create hash-based indexes on an attribute of
type PersonName.
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Submission
You need to submit two files: pname.c containing the C functions that implement the internals of the
PersonName data type, and pname.source containing the template SQL commands to install the
PersonName data type into a PostgreSQL server. Do not submit the pname.sql file, since it contains
absolute file names which are not helpful in our test environment.
Have fun, jas
