Oracle: excluding updates of one column for firing a trigger

Question

In oracle I can specify the columns, which should induce a firing of a trigger:

create or replace trigger my_trigger
before update of col1, col2, col3 on my_         


        

Answer 1

I had the same problem yesterday. I wanted to code a trigger that fired on every field except one, the table had 103 colums.

First I coded:

if (:OLD.col1<>:NEW.col1 or :OLD.col2<>:NEW.col2 or :OLD.col3<>:NEW.col3 ....)

But I had some problems with null values, so I added:

if (NVL(:OLD.col1,0)<>NVL(:NEW.col1,0) or NVL(:OLD.col2,0)<>NVL(:NEW.col2,0)  ....)

But then I had some problems with DATE columns, it became a mess..

I think that the best solution is to list all columns that you want to verify in the "OF":

AFTER INSERT OR UPDATE of cOL1, col2, col3 ... colN ON table1

It was not "elegant" but... it worked perfect.