On Sat, 9 Aug 2003, Jennifer Vargas wrote:
> If you have a many-to-one relationship, such as a contact list where
> several people
> share an address, you may want to delete the child record once the last
> reference to
> it is gone. I don't see how to implement a reference-counting scheme in
> a database.
> What's the right way to accomplish this?
Probably a trigger on update or delete of the referencing table. If
you're not worried about some of the multi-session concurrency problems,
it's a marginally simple plpgsql trigger.