Halting the update from a BEFORE UPDATE trigger

Question

Hello,
I'm writing a trigger which is set to fire before update. One of the possible scenarios requires that the row being updated is not updated but instead deleted. Is it possible to send a DELETE query and then stop the update process so it doesn't spit out an error? I haven't tested this yet, but I'm quite sure it will give an error if it's trying to update a row which has just been deleted.
Thanks,
Pavel

Answer 1

Hi,
Personally, I don't like implement some business logic into trigger... so, why run an update whenever you need a delete ?
I would modify the original code to delete in this case instead of update.
My 2 cents,
Nicolas.
SQL> create table pavel (id number, txt varchar2(10));
Table created.
SQL> insert into pavel values (1, 'This one');
1 row created.
SQL> ed
Wrote file afiedt.buf
  1  create or replace trigger pavel_trg
  2  before update on pavel
  3  for each row
  4  begin
  5  delete from pavel where id = :old.id;
  6* end;
SQL> /
Trigger created.
SQL> update pavel set txt = 'Two';
update pavel set txt = 'Two'
ERROR at line 1:
ORA-04091: table SCOTT.PAVEL is mutating, trigger/function may not see it
ORA-06512: at "SCOTT.PAVEL_TRG", line 2
ORA-04088: error during execution of trigger 'SCOTT.PAVEL_TRG'Message was edited by:
N. Gasparotto