Re: Another view on analysis and ER

From: paul c <>
Date: Wed, 05 Dec 2007 18:04:44 GMT
Message-ID: <0LB5j.6$iU.1_at_pd7urf2no>

David Cressey wrote:
> "Jan Hidders" <> wrote in message

>> Normalization is really only a very minor issue here IMO. I've not had
>> that much personal practical experience in my life but I did work
>> briefly for two big Dutch companies that both had an organization in
>> charge of maintaining the global company data model that integrated
>> all data models from the applications and databases they had. I worked
>> with the guys that did this, and I remember being completely blown
>> away buy how much variation there was in concepts such as employee and
>> order, even within a single company. I still admire these guys.

> "Normalization" as such is a corrective measure against data that turns out
> to have been designed in an unfortunate manner. As such, it's a bottom up
> approach. The approach I outlined above is a top down approach, and
> results in a normalized model (at least up to 3NF) with no effort at
> nromalization as such. The ER model i neither normalized not denormalized.
> I strongly suspect that Bob Badour's approach, centered on propositions,
> is also a top down approach, and that the appropriate binding of attributes
> into relvars is a natural consequence of discovering well formed
> propositions rather than a corrective measure taken after an initial design
> that deviates from normalization. But I don't have up close experience with
> Bob's approach, so I'll defer to Bob's comments in this regard.
> ...

I suspect that two or more equally "correct" normalizations, correct in terms of theory, often suggest themselves. Received on Wed Dec 05 2007 - 19:04:44 CET

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