Re: How to represent category, subcategory, product
From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Thu, 23 Nov 2006 13:35:32 GMT
Message-ID: <Esh9h.23833$cz.362274_at_ursa-nb00s0.nbnet.nb.ca>
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> I like your point that making up tables without first forming the
> predicates is jumping the gun but in this example I don't see how the
> frogs are necessarily a subset of the amphibians (ignoring outside
> information).
Date: Thu, 23 Nov 2006 13:35:32 GMT
Message-ID: <Esh9h.23833$cz.362274_at_ursa-nb00s0.nbnet.nb.ca>
paul c wrote:
> JOG wrote:
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>> * kermit is a member of the set of frogs and of the set of amphibians.
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>> By normalizing to 3NF it becomes clear that you are actually dealing >> with two distinct predicate structures:
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>> * All frogs are amphibians.
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> I like your point that making up tables without first forming the
> predicates is jumping the gun but in this example I don't see how the
> frogs are necessarily a subset of the amphibians (ignoring outside
> information).
If some frogs are not amphibians, then we don't have a category/subcategory problem in the first place. Received on Thu Nov 23 2006 - 14:35:32 CET