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Re: Does Codd's view of a relational database differ from that ofDate&Darwin?[M.Gittens]

From: VC <>
Date: Fri, 8 Jul 2005 20:42:29 -0400
Message-ID: <>

"Jan Hidders" <> wrote in message news:6_Dze.140602$
> VC wrote:
>> "Jan Hidders" <> wrote in message
>> news:5DBze.140518$
>>>VC wrote:
>>>>Let's try another approach. *When* does one need "conceptual objects"
>>>>and "semantic domains" as opposed to just objects and domains ? On what
>>>>specific occasions ? I hope you agree, since you've excised this part
>>>>of my message, that U.o.E vs. U.o.D contradistinction does not make
>>>>much sense. If you do, the may question stands: what is a "conceptual
>>>>object" ?
>>>When you are making a data model there are certain things you want to
>>>describe, and certain things you do not want to describe.
>> As I said before, the stuff you do not want to describe simply does not
>> exist in your hypothetical model, we do not need to talk about it.
> You are right that *in the model* we do not make that distinction. But if
> we talk *about* the model, and especially when we talk about what should
> and should not be in it, then of course we do. When modeller 1 asks
> modeller 2 "Do you think we should describe stacks and linked lists in our
> model?" then the answer might be "No, I don't think these are conceptual
> objects here." For them the question about what is and is not described in
> the model is of course important. That is really all there is to it.

I do not want to be picky, but I still do not see much point in using separate terminology with respect to something you are not going to use ever after you've decided *what* exactly you want to model. A simpler and clearer response to the question whether we are going to model, say, bicycles, would be just a simple "No", instead of enigmatic "I don't think tthey are conceptual objects".

Anyway, since the article that originated my questions does not talk about anything beyond a query language, that is it talks solely about "conceptual objects", then my intention of mapping "conceptual" and "semantic", as bearing no additional meaning, to blanks was correct, right ?

>> P.S. I presume a "semantic domain" is composed of "conceptual
>> objects", right ?
> Yes, actually "semantic domain" and "object type" are the same thing, as
> far as I can see.
> -- Jan Hidders
Received on Fri Jul 08 2005 - 19:42:29 CDT

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