Question

I wrote the trigger for updating the column value in the same table. For Ex I wrote a trigger on metermaster table after update of assettype column , with in the trigger i am trying to update the instantaneousinterval column in the same metermaster table. Its throws the error like this

ERROR: ORA-04091: table PSEB.METERMASTER is mutating, trigger/function
may not see it.

my trigger code is as follows:

CREATE OR REPLACE TRIGGER PSEB.spiupdate
AFTER
update of assettype
ON pseb.metermaster
referencing new as new old as old
    for each row
DECLARE
vassettype number;
resval number(10);
vassettypename varchar2(50);
vmeterid number;
begin
   select :new.assettype,:new.meterid INTO vassettype,vmeterid from dual;
   select assettypename into vassettypename from pseb.METERASSETINSTTYPE where ASSETTYPEID=vassettype;
    select case when assettypename  like 'DT' then 86400 when assettypename  like 'HT' then 3600 when assettypename  like 'FSB' then 86400 end  into resval from pseb.meterassetinsttype where assettypename =vassettypename; 
    update pseb.metermaster set instantaneousinterval=resval where meterid=vmeterid;
end;

I tried to use the

pragma autonomous_transaction;

but it gives the deadlock condition.
ERROR: ORA-00060: deadlock detected while waiting for resource
ORA-06512:

pls help me to fix this issue.

Answer 1

instead of this update statement

update pseb.metermaster set instantaneousinterval=resval where meterid=vmeterid;

use

:new.instantaneousinterval=resval;