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

2. What are stored procedures 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 One Query Wait, receive, process/compute Database Server Internet Reduce roundtrips across the network Can make security easier to manage Are precompiled

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 (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 http://www.postgresql.org/docs/9.1/static/errcodes- appendix.html#ERRCODES-TABLE http://www.postgresql.org/docs/9.1/static/errcodes- 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

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 http://www.postgresql.org/docs/9.1/static/index.html Practical PostgreSQL http://www.faqs.org/docs/ppbook/c19610.htm

31. Stored Procedure in PgAdmin 1 2 3