Question

I am trying to create an Oracle trigger that would update entry_stamp column (type=DATE) on every inserted or updated record for a certain table. Here is my script:

CREATE OR REPLACE TRIGGER mytable_entry_stamp 
AFTER INSERT OR UPDATE ON mytable FOR EACH ROW
BEGIN :NEW.entry_stamp := SYSDATE; END;

I am getting this error:

ORA-04084: cannot change NEW values for this trigger type

Answer 1

From Oracle/PLSQL: AFTER UPDATE Trigger:

• You can not update the :NEW values.
• You can not update the :OLD values.

It appears that Oracle cannot update a record inside AFTER trigger, unlike MSSQL. So it is reserved for logging/audit purposes, i.e. a record can be inserted or updated in another table. After I converted this trigger to BEFORE, it worked flawlessly.