Re: By The Dawn's Normal Light

From: Marshall Spight <mspight_at_dnai.com>
Date: Sat, 23 Oct 2004 18:23:36 GMT
Message-ID: <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. There's also this term "nested relations" but it seems to mean something very specific that I haven't quite nailed down yet.

Marshall Received on Sat Oct 23 2004 - 20:23:36 CEST

Original text of this message