Re: Update on tables when the row doesn't change

On 5/24/05, Sebastian Böck <sebastianboeck@freenet.de> wrote:
> /* 3rd way of separating updates
>    con: unnecessary updates on tables
>    pro: view gets evaluated only 1 time
>
>    Not adressing the problem of unnecessary updates, but the view
>    gets only evaluated one time.
>
> */
>
> CREATE OR REPLACE FUNCTION upd (view_test) RETURNS VOID AS $$
>         DECLARE
>                 NEW ALIAS FOR $1;
>         BEGIN
>                 RAISE NOTICE 'UPDATE';
>                 UPDATE test SET test = NEW.test WHERE id = OLD.id;
>                 UPDATE join1 SET text1 = NEW.text1 WHERE id = OLD.id;
>                 UPDATE join2 SET text2 = NEW.text2 WHERE id = OLD.id;
>                 UPDATE join3 SET text3 = NEW.text3 WHERE id = OLD.id;
>                 RETURN;
>         END;
> $$ LANGUAGE plpgsql;

Control question, I didn't check it, but would it be enough to change from:
   UPDATE join1 SET text1 = NEW.text1 WHERE id = OLD.id;
to:
   UPDATE join1 SET text1 = NEW.text1 WHERE id = OLD.id AND text1 <> NEW.text1?

...  I may be wrong. :)

   Regards,
     Dawid