On Fri, 3 Aug 2001, Kapil Tilwani wrote:
> Right now, I am enforcing uniqueness in three different tables
> (Supplier, Customer, Ledger) thru the front-end by checking thru a
> Union Query. Is it possible to enforce such a uniquenessthru in the
> DB.
Do you mean you want uniqueness of ids across the three tables so that
Customer's id never duplicates a Supplier id for example? If you're
using serial integer ids now (or a sequence), I'd suggest setting them all
to use the same sequence generator, barring wraparound, that should
guarantee uniqueness.
> Irrespective of the above, is it possible to have a foreign
> key check in this (???)
It depends on what you mean. As another poster said, if you mean
between those three tables individually, yes. If you mean a foreign key
to a view itself, like a union view, no.
