From: mcstockX@Xenquery   
      
   "M"  wrote in message   
   news:c7b3da1b.0402171142.639944cb@posting.google.com...   
   | Hello,   
   |   
   | I have a very simple table, and want to create a trigger that updates   
   | the date column entry (with the current date), whenever a row gets   
   | modified.   
   | Is there a simple way of fixing this, or would I have to create 3   
   | extra triggers, a package, etc., as described in most posts about   
   | mutating table errors?   
   | Could you please explain to me WHY this error happens here (I have not   
   | been able to find a clear explanation of what causes them)?   
   |   
   |   
   | create table mvkTest   
   | (bukva char(5),   
   | kogda date);   
   |   
   | insert into mvkTest   
   | values('aaa', sysdate);   
   | insert into mvkTest   
   | values('bbb', sysdate);   
   |   
   | create or replace trigger test_Trigger   
   | after update on mvkTest   
   | for each row   
   | begin update mvkTest   
   | set kogda = sysdate;   
   | end;   
   | /   
   |   
   | update mvkTest   
   | set bukva = 'ccc'   
   | where bukva = 'aaa';   
   |   
   | =======>>>>>>   
   |   
   | update mvkTest   
   |        *   
   | ERROR at line 1:   
   | ORA-04091: table DTI.MVKTEST is mutating, trigger/function may not see   
   | it   
   | ORA-06512: at "DTI.TEST_TRIGGER", line 1   
   | ORA-04088: error during execution of trigger 'DTI.TEST_TRIGGER'   
   |   
   |   
   |   
   | Thank you,   
   | G.   
      
      
   are you used to SQL Server where you have the pseudo-tables for accessing   
   rows affected by the DML?   
      
   in Oracle you reference the values going into the database with the :NEW   
   'record' and the original values with the :OLD 'record'   
      
   so the trigger is more like   
      
   create or replace trigger test_trigger   
   before insert or update  on mvktest   
   for each row   
   begin   
        :new.kogda := sysdate;   
   end;   
      
   simple, no?   
      
   your code, if it would work, would have updated every row in the table (no   
   where clause)   
      
   note:   
   [_] use a BEFORE trigger to set values before the DML is applied to the   
   database   
   [_] use 'INSERT or UPDATE' for a trigger that applies to both DML   
   [_] optionally use the INSERTING and UPDATING keywords (if inserting....)   
   for conditional logic in the same trigger   
      
   -- mcs   
      
   --- SoupGate-Win32 v1.05   
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