Re: Another view on analysis and ER

From: David Cressey <>
Date: Wed, 05 Dec 2007 19:15:01 GMT
Message-ID: <VMC5j.11573$xB.9491_at_trndny06>

"paul c" <> wrote in message news: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
> > to have been designed in an unfortunate manner. As such, it's a bottom
> > 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
> >
> > I strongly suspect that Bob Badour's approach, centered on
> > is also a top down approach, and that the appropriate binding of
> > into relvars is a natural consequence of discovering well formed
> > propositions rather than a corrective measure taken after an initial
> > that deviates from normalization. But I don't have up close experience
> > 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.

I agree with that, but it doesn't address the issue of whether you design an unnormalized schema and then normalize it on the one hand or on the other hand start with something from which you can design a schema that will already be normalized. Received on Wed Dec 05 2007 - 20:15:01 CET

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