Re: How do a non unique index enforces primary key constraint?

From: Mark D Powell <Mark.Powell_at_eds.com>
Date: 20 Oct 2004 17:21:03 -0700
Message-ID: <2687bb95.0410201621.51793ba6@posting.google.com>

faltoobd_at_yahoo.com (hypermodern) wrote in message news:<fcefb078.0410201004.141d9d72_at_posting.google.com>...
> Hi all
> I am preparing for OCP. I have came across this in the student book
> that a non-unique index can enforce a primary key constraint. I don't
> get it. Can anybody explain this please.
>
> Thanks
>
> Fast Eddy

See the Concepts manual chapter on Contraints. A non-unique index enables deferring enforment of the PK constraint until commit time. A unique index would prevent the insertion of a duplicate row at insert time.

HTH -- Mark D Powell -- Received on Wed Oct 20 2004 - 19:21:03 CDT