Re: By The Dawn's Normal Light

From: Dawn M. Wolthuis <dwolt_at_tincat-group.comREMOVE>
Date: Sat, 23 Oct 2004 14:37:06 -0500
Message-ID: <clebtf$oni$1_at_news.netins.net>


"Marshall Spight" <mspight_at_dnai.com> wrote in message news:gkxed.303674$D%.250206_at_attbi_s51...
> "Laconic2" <laconic2_at_comcast.net> wrote in message
news:_M-dnVCpa_yP5efcRVn-jA_at_comcast.com...
> >
> > I claim that it's not useful to have one definition for "relation" for
> > mathematics and an incompatible one for IT. On this point I agree with
> > Dawn.
>
> I agree also.
>
>
> > And it's clear to me that the mathematical definition of "relation"
> > does not force the values in the tuples to be atomic. And it's clear to
me
> > that the definition I always learned for 1NF does force the values in
the
> > tuples to be atomic.
>
> Yeah, that's true.
>
>
> > So, if someone wants to adjust the definition of 1NF so that it no
longer
> > requires atomic values, I would prefer that they invent a new term,
like
> > "Date-Darwen Normal form". There is precedent for this. "Boyce-Codd
Normal
> > Form" was sandwiched between 3NF and 4NF, rather than renumbering the
> > normal forms.
>
> Fair enough.
>
>
> > If someone wants to change the definition of "Relation", I would prefer
> > that they invent a new term, like "normal relation".
> > Then they can say that a "normal relation is in 1NF (and may also be in
> > other normal forms)".
> >
> > If we did this, we could talk about "relations" as such, and talk
about
> > "normal relations" when we need to.
>
> It seems like the term "NFNF" is fairly established as the term for
> relations that allow attributes to be relations or lists; that works for
> me.

I see NF^2 -- not able to write it here, at least as often (pronounced "NF squared" when I've heard it). But that might just be the stuff I read and not generally accepted??

> There's also this term "nested relations" but it seems to mean
> something very specific that I haven't quite nailed down yet.

Yes, that seems to imply that the only non-scalar (?), text values are relations. --dawn

>
> Marshall
Received on Sat Oct 23 2004 - 21:37:06 CEST

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