Re: ON UPDATE trigger question

On Wednesday 12 September 2007 15:56:13 Josh Trutwin wrote:
> If I create an ON UPDATE trigger run on each row after update, does
> the trigger fire only on rows affected by the update or for all rows?
>
> For example:
>
> CREATE TRIGGER my_update_trigger
>    AFTER UPDATE ON my_table
>    FOR EACH ROW
>    EXECUTE PROCEDURE my_update_proc;
>
> UPDATE my_table SET my_val = my_val * 2;
>
> Will the trigger fire on rows that have NULL for my_val?

I haven't tested what you asked (you can do that easily), but if this is your
concern and if you have a huge table you might want to add a WHERE
clause: "WHERE my_val IS NOT NULL".


--
Jorge Godoy      <jgodoy@gmail.com>