Re: trigger on DELETE

On Wed, 11 Jul 2001, Phuong Ma wrote:

> I'm trying to define a trigger that copies the row to be deleted into
> another table (which is the inventory_audit table) before it does the
> delete from the original table (which is the inventory table).
>
> CREATE FUNCTION inv_audit_mod () RETURNS OPAQUE AS '
>     BEGIN
>
>         NEW.user_aud := current_user;
>         NEW.mod_time := ''NOW'';
>
>         INSERT INTO inventory_audit
>         SELECT * FROM inventory WHERE id=NEW.id;
>
>         RETURN NEW;
>     END;
> ' LANGUAGE 'plpgsql';
>
>  CREATE TRIGGER inv_audit_mod BEFORE
>         DELETE ON inventory
>         FOR EACH ROW EXECUTE PROCEDURE inv_audit_mod();
>
> Ok, the function works only with a trigger that is defined as ON INSERT
> OR UPDATE.  If I try to define a trigger for ON DELETE and then delete a
> row from the table, there is nothing in the 'NEW' variable to return.  I
> get an error message.  If I define the function to return NULL, 0, or
> nothing, then it comes up with a type mis-match error.  Is there anyone
> who can help?  Thanks.

I believe you want to use OLD rather than NEW for a delete trigger.