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you do not have to add a primary key constraint to a table if it is
already uniquely keyed. RI constraints are *not* dependent on whether a
"master" file is uniquely keyed or not, just that the key value written to
the "detail" file has a matching key in the "master" file
Thanks,
Tommy Holden
From: "James H. H. Lampert" <jamesl@xxxxxxxxxxxxxxxxx>
To: Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxx>
Date: 12/14/2009 03:26 PM
Subject: Re: Constraints, anyone?
Sent by: midrange-l-bounces@xxxxxxxxxxxx
Tommy.Holden@xxxxxxxxxxxxxxxxxxxxx wrote:
primary key = unique keyed PF
So why is it available as a constraint, as opposed to simply creating
the PF as keyed? And conversely, assuming the PF is already keyed, is it
necessary to add a primary key constraint to the file in order to use it
in referential constraints?
--
JHHL
midrange.com
