Re: teaching relational basics to people, questions

From: Jan Hidders <>
Date: Mon, 21 Dec 2009 15:13:40 -0800 (PST)
Message-ID: <>

On 21 dec, 23:07, r..._at_raampje.lan (Reinier Post) wrote:
> Jan Hidders wrote:
> >On 16 nov, 20:42, Sampo Syreeni <> wrote:
> >> So now I bump into my first real surprise, and the chills immediately
> >> go down my spine. That's Date et al.'s answer regarding the
> >> implications between 6NF and DK/NF,
> >at
> >> . In there they flat out state that DK/NF doesn't imply 6NF.
> >> So, my first question is, can this really be true? I mean, this seems
> >> highly suspect to me: since 6NF is a normal form like any other
> I don't think so.  It's hard fo me to tell, because I just did the
> required math and it turns out don't have $60 to spend on the book
> which contains the definition of 6NF required for this discussion,
> but if I can get by the Google Books preview, it appears to involve some
> degree of interpretation of domain values (as being totally ordered).
> Normal normal forms don't do this.

Wikipedia is your friend:


Whether you can call it a normal form or not is of course largely a matter of definition, but it clearly is different from the other ones. It does for example not remove redundancy or update anomalies, which was pretty much the whole point of the other normal forms.

Received on Tue Dec 22 2009 - 00:13:40 CET

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