Complex Primary Key Validation

From: michael streeton <mstreeton_at_caci.co.uk>
Date: Mon, 21 Jan 2002 16:22:01 -0000
Message-ID: <1011630061.12717.0.nnrp-14.c3ad5001@news.demon.co.uk>

I have a table that holds data that is valid only for a time period. The primary key for the table is a composite of an id (not unique); effective from date; effective to date. e.g.

id 1 effective_from 1/1/2002 effective_to 10/1/2002 id 1 effectiive_from 11/1/2002 effective to 31/1/2001

I would also like to enforce some constraint that validated the effective from and to dates do not overlap and would prevent the following:

id 1 effective_from 1/1/2002 effective_to 15/1/2002 id 1 effectiive_from 12/1/2002 effective to 31/1/2001

Any Ideas

Many Thanks

Mike Received on Mon Jan 21 2002 - 10:22:01 CST