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>



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 Tue Nov 17 2009 - 17:08:30 CST

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