Re: One-To-One Relationships

From: David Cressey <>
Date: Fri, 30 Nov 2007 19:51:21 GMT
Message-ID: <ZQZ3j.26$Uy.25_at_trndny07>

"paul c" <> wrote in message news:Q9Z3j.8332$UQ1.1468_at_pd7urf1no...
> David Cressey wrote:
> >
> > Note that "attributes, values, and domains" are common elements to the
> > model and to the relational model. They provide a brdige from one kind
> > modeling to the other.
> Of course people in different camps of any field will sometimes adopt
> the other side's lingo and call it their own, it's rampant among nations
> today. But attributes, values and domains aren't logical RM terms
> because they are "logical" nor because "they can be seen to exist" nor
> because they offer a bridge to some other theory but because they are
> necessary to define that model's operation.

The terms are not common because they are a bridge. They are a bridge because they are common. When Chen devised ER, and when I learned ER, it wasn't as a member of some "camp" or another. AFAIK, Chen never held that ER was a substitute for relational modeling. Rather, ER was a useful way ot look at the data, while leaving open the door to implementing in a relational system or some other kind of system (at the time network or hierarchical, which I kinda glossed over as CODASYL).

This whole division of discussion about the field into "camps" is degrading, in my view. I am not mmember of the "entity relational camp" or of the "relational camp" or of the "Codd camp" or the "Date camp" or the "Nelson Pick camp" or, God forbid of the "object oriented camp". But I find interesting ideas in all of the above points of view. I had an opportunity to exercise ideas from one POV more than others, but I never had to join a "camp".

I'm not about to do that now. Received on Fri Nov 30 2007 - 20:51:21 CET

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