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

On 5/24/05, Sebastian Böck <sebastianboeck(at)freenet(dot)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