Re: regarding triggers

On 1/10/06, Jaime Casanova <systemguards(at)gmail(dot)com> wrote:
> On 1/10/06, surabhi.ahuja <surabhi(dot)ahuja(at)iiitb(dot)ac(dot)in> wrote:
> >
> >
> > is there an advantage of using a trigger? when the same job can be performed
> > by a stored procedure?
> >
>

a trigger is actually a stored procedure... the advantage is that it's
called automagically when an event happens...

>
> > one more question is as follows:
> > suppose i have a table x, with a primary attribute 'a'
> >
> > and i have a table y, with the primary attribute 'b', and a foreign key 'a'.
> >
> > suppose i say delete from x where a = '1',
> >
> > it means that not only the rows from x get deleted but also rows from y get
> > deleted.
> >
>

only if you specified ON DELETE CASCADE at FOREIGN KEY creation

> > now i have a trigger which is written for deletes taking place from the
> > table y.
> >
> > however if i say delete from x where a = '1',
> >
> > will the trigger (mentioned above) still be called? (because delete are also
> > taking place from the table y)
> >
>

if the DELETE will CASCADE, yes

> > thanks,
> > regards
> > Surabhi
>
>

--
regards,
Jaime Casanova
(DBA: DataBase Aniquilator ;)