Re: teaching relational basics to people, questions
From: <compdb_at_hotmail.com>
Date: Tue, 17 Nov 2009 15:08:30 -0800 (PST)
Message-ID: <0abb73d9-7eea-48d5-bc95-627850ea7abb_at_g10g2000pri.googlegroups.com>
Date: Tue, 17 Nov 2009 15:08:30 -0800 (PST)
Message-ID: <0abb73d9-7eea-48d5-bc95-627850ea7abb_at_g10g2000pri.googlegroups.com>
On Nov 16, 11:42 am, Sampo Syreeni <de..._at_iki.fi> wrote:
> other hand DK/NF is by definition a normal form where any constraint
> whatsoever follows from the domain and key ones
Go read a definition carefully. Eg wiki dknf.
It's in DK/NF iff all constraints follow from the domain and key ones.
So it's not in DK/NF iff some constraint doesn't follow from the
domain and key ones,
In other words, if there other constraints is just isn't *in* DK/NF.
(It's not a very useful concept.)
philip Received on Wed Nov 18 2009 - 00:08:30 CET