Re: one to many

On Sun, 16 May 2004, Dennis Gearon wrote:

> CC me please.
>
> How do I set up a one to many relationship in Postgres, (any DB for that
> matter.)
>
> I.E., if a delete or update of a child table causes a row in the parent
> table to no longer refer to any rows in the child table, to either cause
> Postgres to error out or delete the parent? I can see it does it for
> when a parent is upudated or deleted.

I don't think there's any built in direct way to do this right now, but
you could probably build triggers that would do it for you (the current
foreign key triggers might give a starting point. You'd probably also
want to use CREATE CONSTRAINT TRIGGER to be able to defer the trigger
(similarly to how the foreign key deferred works).