Newbie: DBMS_OUTPUT problem.

Question

Hi all,
I have a very basic question...
I wrote the code for the procedure as this
SQL> create or replace procedure looptest as
  2   begin
  3    for idx in 3..1 loop
  4   dbms_output.put_line('a');
  5    dbms_output.put_line (idx);
  6   for idx1 in 1..3 loop
  7   dbms_output.put_line('b');
  8     dbms_output.put_line (idx1);
  9   end loop;
10   end loop;
11*   end;
SQL> /
Procedure created.
SQL> exec looptest;
PL/SQL procedure successfully completed.
SQL> set serveroutput on;
SQL> commit;
Commit complete.
SQL> exec looptest;
PL/SQL procedure successfully completed.I wanted to see the result of running this procedure...
a.k.a some output like 3, 1, 2, 3, 2, 1, 2,... etc
question 1 : Why am i not able to see the result??
question 2: What should be done to see the result
Thanks in advance..

Answer 1

DBMS_OUTPUT is a server-side API (PL/SQL package). It allows PL/SQL code to write into a session static/persistent buffer in PL/SQL.
A client, like SQL*Plus, can then display the contents of this buffer after the PL/SQL code has completed execution.
The SQL*Plus command to enable this client feature (of displaying the buffer) is SET SERVEROUTPUT ON.
SQL> set serveroutput on
SQL> begin
2 for i in 1..10
3 loop
4 DBMS_OUTPUT.put_line( 'inside loop | counter='||i );
5 end loop;
6 end;
7 /
inside loop | counter=1
inside loop | counter=2
inside loop | counter=3
inside loop | counter=4
inside loop | counter=5
inside loop | counter=6
inside loop | counter=7
inside loop | counter=8
inside loop | counter=9
inside loop | counter=10
PL/SQL procedure successfully completed.
SQL>