How to get around ora-ORA-04091: table SSBOSS.SSTRMAST is mutating, trigger

Question

hi,
Does anyone know how one would get around this problem please ?
Here is my dbase trig:
CREATE OR REPLACE TRIGGER SSBOSS.new_not_greater_than_net
BEFORE INSERT OR UPDATE OF newrent ON SSBOSS.SSTRMAST
REFERENCING NEW AS new OLD AS old
FOR each row
DECLARE
not_permitted EXCEPTION;
vnum number := ssboss.nik_f;
BEGIN
IF :new.NEWRENT > vnum then
--AND :old.DELETED = 'N' THEN
RAISE not_permitted;
END IF;
EXCEPTION
WHEN not_permitted THEN
RAISE_APPLICATION_ERROR
(-20001, 'NEWRENT:'||:new.newrent||' '||'OLDRENT:'||' '||:old.netrent||'Action not permitted. Contribution (sstrmast.newrent) value '
||:new.NEWRENT
||' exceeds GROSS rental value (sstrmast.netrent) ');
END;
Here is my problem:
SQL> update sstrmast set newrent = 11;
update sstrmast set newrent = 11
ERROR at line 1:
ORA-04091: table SSBOSS.SSTRMAST is mutating, trigger/function may not see it
ORA-06512: at "SSBOSS.NIK_F", line 4
ORA-06512: at "SSBOSS.NEW_NOT_GREATER_THAN_NET", line 4
ORA-04088: error during execution of trigger 'SSBOSS.NEW_NOT_GREATER_THAN_NET'
I understand why but not how to correct?
Thanks,
nikolia.

Answer 1

Hello,
This problem as you might be knowing occurs when you try to select the data from the same table on which the trigger is written. Also this problem is only with the row level trigger and not with the statement level trigger. However the limitation of the statement level trigger is it can not refer to :NEW or :OLD. So now the solution is to capture the value of :NEW or :OLD in the row level trigger (no select statement here) and store it in some global variable. And how do you get the global variable? Using package specification ! a variable declared in a package specification is global in nature. Then use the value so stored in the statement level trigger in the select statement. It will work. Other solution is to use pragma autonomous transaction. Try and let us know. All the best.
Regards