1. Procedures Oracle & MySQL
Prof. Arfaoui. COM390 Chapter 5
Oracle11g: PL/SQL Programming

2. Chapter Objectives
After completing this lesson, you should be able to understand:
Named program units
Creating a procedure
Calling a procedure from another procedure
Using the DESCRIBE command with procedures
Debugging procedures using DBMS_OUTPUT
Using subprograms
The scope of variables, exception handling and transaction control
Removing procedures
Oracle11g: PL/SQL Programming

3. Brewbean’s Challenge
Develop programming modules for specific tasks such as calculating
taxes or updating inventory
Oracle11g: PL/SQL Programming

4. Named Program Units
PL/SQL blocks executed thus far have been anonymous blocks
Now we will assign a name to the block and save it in the database as a stored program unit
This makes program units reusable
Oracle11g: PL/SQL Programming

5. Stored Routines Procedures, Functions, Triggers, Packages
Fast - A stored routine is held on the database server.
Reusability - A stored routine is created once but used many times.
Code efficiency - Stored routines also reduce code duplication.
Debugging and testing an application also becomes easier.
Application security - Application only sees the data it needs.
Oracle11g: PL/SQL Programming

6. Create Procedure Statement Syntax
Oracle11g: PL/SQL Programming

7. Parameters – Make Program Units Reusable
Mechanisms used to send values in and out of program units
IN – is the default mode. When you define an IN parameter in a stored procedure, the calling program has to pass an argument to the stored procedure. In addition, the value of an IN parameter is protected.
OUT – the value of an OUT parameter can be changed inside the stored procedure and its new value is passed back to the calling program.
IN OUT – an IN OUT parameter is a combination of IN and OUT parameters.
The calling program may pass the argument.
The stored procedure can modify the IN OUT parameter.
Pass the new value back to the calling program.
Oracle11g: PL/SQL Programming

8. Create Procedure - Oracle
Procedure to determine shipping cost
Oracle DBMS
CREATE OR REPLACE PROCEDURE SHIP_COST_SP( p_qty IN Numeric, p_ship OUT Numeric) AS
BEGIN
IF p_qty > 10 THEN
p_ship := 11.00;
ELSIF p_qty > 5 THEN
p_ship := 8.00;
ELSE
p_ship := 5.00;
END IF;
END;
Oracle11g: PL/SQL Programming

9. Create Procedure - MySQL
MySQL DBMS
DELIMITER //
CREATE PROCEDURE SHIP_COST_SP(IN p_qty Numeric, OUT p_ship Numeric)
BEGIN
IF p_qty > 10
THEN SET p_ship = 11.00;
ELSEIF p_qty > 5
THEN SET p_ship = 8.00;
ELSE
SET p_ship = 5.00;
END IF;
END//
DELIMITER;

10. Execute Procedure - Oracle
Oracle DBMS
DECLARE
lv_ship_num NUMERIC(6,2);
BEGIN
SHIP_COST_SP(7 , lv_ship_num);
DBMS_OUTPUT.PUT_LINE('Ship Cost = ' || lv_ship_num);
END;
Declare a variable to hold value from OUT parameter
Call procedure addressing both parameters
Display value returned to verify
Note: Parameter arguments are passed positionally by default
Oracle11g: PL/SQL Programming

11. Execute Procedure - MySQL
MySQL DBMS
CALL SHIP_COST_SP(7
SELECT CONCAT('Ship Cost = ' ) AS "OUTPUT";

12. IN OUT mode - Oracle Oracle DBMS
Send value in and out via the same parameter
Oracle DBMS
CREATE OR REPLACE PROCEDURE phone_fmt_sp(p_phone IN OUT VARCHAR2) AS
BEGIN
p_phone := '(' || SUBSTR(p_phone,1,3) || ')'
|| SUBSTR(p_phone,4,3) || '-'
|| SUBSTR(p_phone,7,4);
END;
Oracle11g: PL/SQL Programming

13. IN OUT mode - MySQL MySQL DBMS DELIMITER //
CREATE PROCEDURE phone_fmt_sp (INOUT p_phone VARCHAR(25))
BEGIN
SET p_phone = CONCAT('(' , SUBSTR(p_phone,1,3) , ')'
, SUBSTR(p_phone,4,3) , '-'
, SUBSTR(p_phone,7,4));
END//

14. Execute Procedure - Oracle
Oracle DBMS
Declare
fmt_Phone varchar(200) :=' ';
begin
phone_fmt_sp(fmt_Phone);
DBMS_OUTPUT.PUT_LINE(fmt_Phone);
end;

15. Execute Procedure - MySQL
MySQL DBMS
= ' ';
CALL
AS "OUTPUT";

16. Calling a Procedure from another procedure
Oracle DBMS
CREATE OR REPLACE PROCEDURE ORDER_TOTAL_SP
(p_bsktid IN number,
p_cnt out number,
p_sub out number,
p_ship out number,
p_total out number) AS
BEGIN
DBMS_OUTPUT.PUT_LINE('order total proc called');
SELECT SUM(quantity), SUM(quantity * price) into p_cnt, p_sub
FROM bb_basketitem
WHERE idbasket = p_bsktid;
ship_cost_sp(p_cnt, p_ship);
p_total := NVL(p_sub,0) + NVL(p_ship,0);
DBMS_OUTPUT.PUT_LINE('order total proc ended');
END;
Calling procedure ship_cost_sp
Oracle11g: PL/SQL Programming

17. Remove a Procedure DROP PROCEDURE procedure_name;
Oracle11g: PL/SQL Programming

18. TO DO
Execute ORDER_TOTAL_SP in Oracle
Create the equivalent MySQL Stored procedure to ORDER_TOTAL_SP
Call ORDER_TOTAL_SP in MySQL

19. DESCRIBE Command | Oracle & MySQL
Lists the parameters of a program unit
Oracle: DESCRIBE ORDER_TOTAL_SP;
MySQL: SHOW CREATE PROCEDURE phone_fmt_sp;
Oracle11g: PL/SQL Programming

20. Debugging with DBMS_OUTPUT
Oracle11g: PL/SQL Programming

21. Debugging with DBMS_OUTPUT
Oracle11g: PL/SQL Programming

22. Subprograms A program unit defined within another program unit:
Must be declared in the DECLARE section of the containing program unit
Can only be referenced by the containing program unit
Oracle11g: PL/SQL Programming

23. Variable Scope When nesting blocks, are variables shared?
Inner blocks can use variables from outer blocks
Oracle11g: PL/SQL Programming

24. Variable Scope (continued)
Oracle11g: PL/SQL Programming

25. Exception-HandlingFlow
Oracle11g: PL/SQL Programming

26. Transaction Control Scope
The scope refers to the group of DML statements that are affected by a particular transaction control statement
By default, a session has a single DML queue and a transaction control statement would affect all DML in the queue regardless of which program unit initiated the statement
DML statements of a program unit can be treated separately or as an autonomous transaction
Oracle11g: PL/SQL Programming

27. Autonomous Transaction
The pragma instructs the PL/SQL compiler to establish a PL/SQL block as autonomous or independent.
Oracle11g: PL/SQL Programming

28. Summary
Named program unit assigns a name to a program unit so it can be reused
Parameters are used to pass values in and out of program units
Stored program units are saved in the database
Parameter modes include: IN, OUT, and IN OUT
Use DBMS_OUTPUT.PUT_LINE statement to debug
Oracle11g: PL/SQL Programming

29. Summary (continued)
A subprogam is a procedure declared within another procedure
Variable scope must be considered with nested blocks
Autonomous transactions must be explicitly created
Remove a procedure with the DROP PROCEDURE command
Oracle11g: PL/SQL Programming