Subprograms

The PL/SQL has two types of subprograms known as the procedures and functions that can take parameters and be invoked. As the following example represents, a subprogram is like a miniature program, start with a header followed by an optional declarative part, an executable part, and an optional exception-handling part:

PROCEDURE award_bonus (emp_id NUMBER) IS

bonus REAL;

comm_missing EXCEPTION;

BEGIN

SELECT comm * 0.15 INTO bonus FROM emp WHERE empno = emp_id;

IF bonus IS NULL THEN

RAISE comm_missing;

ELSE

UPDATE payroll SET pay = pay + bonus WHERE empno = emp_id;

END IF;

EXCEPTION

WHEN comm_missing THEN

...

END award_bonus;

If called, this procedure accepts an employee number. And it uses the number to select the employee's payment from a database table and, at the similar time, calculate a 15% bonus. Now, it checks the bonus amount. If the bonus is zero or null, an exception is raised; or else, the employee's payroll record is updated.