Re: Need your help

Jie Liang wrote:
> e.g.
> Try:
>
> CREATE TABLE emp (
>     id int4 primary key,
>     empname text,
>     salary int4,
>     last_date datetime,
>     last_user name);
>
> CREATE FUNCTION emp_stamp () RETURNS OPAQUE AS
>     BEGIN
>    update emp set last_date=''now''::timestamp where id=NEW.id;
>         RETURN NEW;
>     END;
> ' LANGUAGE 'plpgsql';
>
> CREATE TRIGGER emp_stamp BEFORE UPDATE ON emp
>     FOR EACH ROW EXECUTE PROCEDURE emp_stamp();
   Not  sure  if it works this way at all, but the update on emp   table is definitely a wasted scan. And  the
'now'::timestamp  will  be  evaluated at the first function call - never again;   not sure if he wanted that behaviour
either.
       CREATE FUNCTION emp_stamp () RETURNS opaque AS '       BEGIN           new.last_date := now();           RETURN
new;      END;'       LANGUAGE 'plpgsql';
 
   Is the correct trigger for this purpose.


Jan

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