Re: Trigger.. AFTER and BEFORE with specific column changed

On 04/01/2012 11:45 AM, Albert wrote:
> *I'm trying to follow this :*
>
>
> CREATE TRIGGER check_update
> *BEFORE* UPDATE ON accounts
> FOR EACH ROW
> WHEN (OLD.balance IS DISTINCT FROM NEW.balance)
> EXECUTE PROCEDURE check_account_update();
>
> *but with AFTER instead of BEFORE. and I'm keep getting error on or near
> WHEN.

What is the error message?

> does that because i have to use BEFORE ? what if i need to execute the
> procedure after updating column and it has really changed.*

Depends what the procedure is doing. For more detail on what the WHEN
does in BEFORE and AFTER triggers see here:
http://www.postgresql.org/docs/9.0/interactive/sql-createtrigger.html

Look for the Notes section.

>
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>

--
Adrian Klaver
adrian(dot)klaver(at)gmail(dot)com