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

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. That is the distinction between U.o.D and U.o.E. What you seem to be asking is if there is somehow an objective quality that distinguishes the objects in the U.o.D from those that are not in it. But since this is a relative notion that depends upon the purpose of the model, there is no such objective quality.

Does that help you?

• Jan Hidders