DBMS_OUTPUT:

The Package DBMS_OUTPUT enables you to display output from the PL/SQL subprograms and blocks, that makes it easier to test and debug them. The procedure put_ line results the information to the buffer in the SGA. You can display the information by calling the procedure get_line or by setting the SERVEROUTPUT ON in the SQL*Plus. For illustration, assume that you create the stored procedure which is as shown below:

CREATE PROCEDURE calc_payroll (payroll OUT NUMBER) AS

CURSOR c1 IS SELECT sal, comm FROM emp;

BEGIN

payroll := 0;

FOR c1rec IN c1 LOOP

c1rec.comm := NVL(c1rec.comm, 0);

payroll := payroll + c1rec.sal + c1rec.comm;

END LOOP;

/* Display debug info. */

DBMS_OUTPUT.PUT_LINE('Value of payroll: ' || TO_CHAR(payroll));

END;

Whenever you issue the commands below, the SQL*Plus display the value assigned by the procedure to the parameter payroll:

SQL> SET SERVEROUTPUT ON

SQL> VARIABLE num NUMBER

SQL> CALL calc_payroll(:num);

Value of payroll: 31225