Can't you check it using something like this: IF OLD.modified = NEW.modified THEN NEW.modified = NOW(); END IF; RETURN NEW;
Susan -----Original Message----- From: pgsql-general-ow...@postgresql.org [mailto:pgsql-general-ow...@postgresql.org] On Behalf Of Johan Andersson Sent: Wednesday, July 07, 2010 6:49 AM To: pgsql-general@postgresql.org Subject: [GENERAL] Trigger for modification timestamp column Hello! I am trying to write a trigger for updating a modification column and am having some trouble getting it to behave as I want. The trigger should set the column to the supplied value if it is set in the UPDATE statement and to the current timestamp [NOW()] if it is not. The problem is that I don't know how to check if the column is set or not. I can check the column's value for NULL but that doesn't work if I want the column to accept NULL values (meaning "unmodified"). I would like something like: CREATE FUNCTION update_modified() RETURNS TRIGGER AS $$ BEGIN IF NOT isset(NEW.modified) THEN NEW.modified = NOW(); END IF; RETURN NEW; END; $$ LANGUAGE 'plpgsql'; Does anyone know how to do this? Thanks in advance! / Johan -- View this message in context: http://old.nabble.com/Trigger-for-modification-timestamp-column-tp29096359p29096359.html Sent from the PostgreSQL - general mailing list archive at Nabble.com. -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
