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@ursa-nb00s0.nbnet.nb.ca>

paul c wrote:

> JOG wrote:
> ...
>

>> * kermit is a member of the set of frogs and of the set of amphibians.

>
> ...
>

>> By normalizing to 3NF it becomes clear that you are actually dealing
>> with two distinct predicate structures:

>
> ...
>

>> * All frogs are amphibians.

>
> ...
>
> 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 - 07:35:32 CST