1. Stored Procedure used in PosgreSQL
Professor: Dr. Shu-Ching Chen
TA: Hsin-Yu Ha

2. What are stored procedure
A subroutine available to applications that access a relational database system.
PL/pgSQL : A loadable procedural language.
Creates functions and trigger procedures
Adds control structures
Performs complex computation
Inherits all user-defined types, functions
Can be defined to be trusted by the server
Easy to use

3. Why do we need stored procedure
Reduce roundtrips across the network
Can make security easier to manage
Are precompiled
One Query
Wait, receive, process/compute
Database Server
Internet

4. Structure of PL/pgSQL

5. Declarations (1)
Declaring PL/pgSQL variable

6. Declarations (2)
Declaring PL/pgSQL variable and assigning values

7. Declarations (3) Declaring Function Parameters by using Alias
(1) directly give a name to the parameter in the command
(2) name ALIAS FOR $n;

8. Declarations (4)
Directly using argument variables

9. Declarations (5)
Attributes
%TYPE attribute

10. Declarations (6)
Attributes
%ROWTYPE attribute

11. Comment syntax
Single-line comments
Block comments

12. Basic Statements (1) Assignment
Executing a Command with NO RESULT – PERFORM

13. Basic Statements (2)
Executing a Command with a Single-row result

14. Basic Statements (3)
Example

15. Basic Statements (4)

16. Basic Statements (5)
FOUND – Boolean variable

17. Control Structures(1)
RETURN expression

18. Control Structures(2) IF statements IF … THEN IF … THEN … ELSE
IF … THEN … ELSIF … THEN … ELSE

19. Control Structures(3) CASE statements
CASE … WHEN … THEN … ELSE … END CASE
CASE WHEN … THEN … ELSE … END CASE

20. Control Structures(4)
LOOP
EXIT

21. Control Structures(5)
CONTINUE
WHILE

22. Control Structures(6)
FOR (Integer Variant)

23. Control Structures(7)
FOR (Looping through query results)

24. Control Structures(8) Trapping Errors
appendix.html#ERRCODES-TABLE

25. Cursors (1)
Declaring Cursor Variables
OPEN FOR query

26. Cursors (2) Using Cursors FETCH MOVE NEXT PRIOR FIRST LAST
ABSOLUTE count
RELATIVE count
FORWARD
BACKWORD
Using Cursors
FETCH
MOVE

27. Cursors (3)
Using Cursors
CLOSE
Returning Cursor

28. Cursors (4)
Looping Through a Cursor’s Result

29. Errors and Messages
RAISE
Example

30. Reference PostgreSQL Manuals PostgreSQL 9.1 Practical PostgreSQL
Practical PostgreSQL