Database trigger

Question

Hello Forum members,
I have a table:
quarter,config
q1-2006 10
q4-2007 50
q2-2006 30
I want to replace config for other quarters based on current quarter ie i want 10,30 to be replaced by 50.
SQL> select 'Q' || TO_CHAR( sysdate, 'Q') || '-' || TO_CHAR( sysdate, 'YYYY') from dual;
'Q'||TO
Q4-2007
I have written the following trigger but am getting mutating trigger error.
1 CREATE OR REPLACE TRIGGER quarter_test1
2 before INSERT
3 ON quarter_test1
4 FOR EACH row
5 BEGIN
6 update quarter_test1 set config=(select config from quarter_test1 where quarter =
7 (select 'Q' || TO_CHAR( sysdate, 'Q') || '-' || TO_CHAR( sysdate, 'YYYY') from dual));
8* end;
Can you please guide me
Cheers

Answer 1

CREATE OR REPLACE TRIGGER quarter_test1
   before INSERT
   ON quarter_test1
   FOR EACH row
BEGIN
   update quarter_test1                                                                            --+                          
      set config = (select config from quarter_test1                                                 | put this in a procedure
                     where quarter = 'Q'||TO_CHAR( sysdate,'Q')||'-'||TO_CHAR( sysdate,'YYYY'));   --+
end;or you can try by creating a procedure and put those UPDATE codes in the procedure. then call the same procedure inside your trigger.
create or replace procedure proc_quarter as
begin
   update quarter_test1                                                                           
      set config = (select config from quarter_test1                                              
                     where quarter = 'Q'||TO_CHAR( sysdate,'Q')||'-'||TO_CHAR( sysdate,'YYYY'));  
end;
CREATE OR REPLACE TRIGGER quarter_test1
   before INSERT
   ON quarter_test1
   FOR EACH row
BEGIN
   proc_quarter;
end;