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Re: Pizza Example

From: Jan Hidders <jan.hidders_at_REMOVETHIS.pandora.be>
Date: Tue, 13 Apr 2004 22:34:18 GMT
Message-ID: <KVZec.70676$MG1.4809827@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.

Received on Tue Apr 13 2004 - 17:34:18 CDT

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