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Re: Pizza Example

From: Dawn M. Wolthuis <dwolt_at_tincat-group.com>
Date: Tue, 13 Apr 2004 19:33:56 -0500
Message-ID: <c5i0u0$qiv$1@news.netins.net>


"Jan Hidders" <jan.hidders_at_REMOVETHIS.pandora.be> wrote in message news:KVZec.70676$MG1.4809827_at_phobos.telenet-ops.be...
> Eric Kaun wrote:
> >
> > OK, I expressed myself badly. Logically, the relational user sees values
in
> > relations. The types of those values can be anything, including lists
and
> > such, but there shouldn't be operators in the data model to manipulate
> > those - rather, those are user-defined operators for the specified
types.
>
> So, one would expect that the NEST and UNNEST operators of the nested
> relational algebra would not be allowed, wouldn't one? I know I would.
> What else could "logically expose" mean for a relation-valued column? Or
> the nested relational calculus, which doesn't have such operators, but
> still allows you to operate on (and combine) the nested sets, would that
> be Ok?
>
> > Is that better? Date's paper "What First Normal Form Really Means" talks
> > about this in great detail...
>
> Ah, well, let me say here and now that I'm not a big fan of Chris Date,
> to put it mildly, and the arrogance of dbdebunk makes me physically
> sick. I know the paper you refer to, and I find it rather unconvincing.

Ditto on all three points in that last paragraph with the caveat that I am impressed with Date (so a fan to that extent) even though I disagree with him on quite a bit. I know that it is either far too easy or far too difficult to disagree with me when I lack precision -- Date lays it out there so that in some ways it is much easier to find points of disagreement with him than with others and I appreciate that. --dawn Received on Tue Apr 13 2004 - 19:33:56 CDT

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