Re: Proposal: 6NF
From: Bob Badour <bbadour_at_pei.sympatico.ca>
Date: Thu, 05 Oct 2006 18:00:22 GMT
Message-ID: <WKbVg.817$cz.11162_at_ursa-nb00s0.nbnet.nb.ca>
>
>
> Suppose you want a list of all animals which lay few to no eggs, with no
> eggs taken to include the inapplicability of the whole concept of laying
> anything.
Date: Thu, 05 Oct 2006 18:00:22 GMT
Message-ID: <WKbVg.817$cz.11162_at_ursa-nb00s0.nbnet.nb.ca>
Sampo Syreeni wrote:
> On 2006-10-05, Roy Hann wrote:
>
>> I always suspect an erroneous intention when I seem to need an outer >> join. Animal is a supertype of bird. Why should I expect to be able to >> ask how many eggs a camel lays?
>
>
> Suppose you want a list of all animals which lay few to no eggs, with no
> eggs taken to include the inapplicability of the whole concept of laying
> anything.
Furthermore, at the time your code is expected to be
> finalized, you only know that there will be animals, some of which lay
> eggs, but you don't know which kinds of properties all of the animals
> eventually described in the database might have.
Ah, but one will have to know what those are before one commits the schema and one will have to know the properties of interest before one writes a query.
[further long-winded ramblings snipped] Received on Thu Oct 05 2006 - 20:00:22 CEST