Re: does a table always need a PK?

Em Tue, 26 Aug 2003 13:53:22 +0000, Christopher Browne escreveu:

> I'm still a little suspicious of the way some of the type inheritance
> in Tutorial D works; some of it looks as though it's actually leading
> to a hierarchical structure, which would break some of the
> "relationality." Of course, it could be that I am misreading it; the
> "Tutorial" is not much of a tutorial...

        Actually I think you are misunderstanding it. The hierarchy of types in _TTM_ (of which Tutorial D is but a possible implementation) is not a requirement, and in fact D&D have given their blessing to its omission in Alphora Dataphor D4 v2.

        And as always, a hierarchy is just a representation. If needs be, we can store it as relations in the data dictionary...

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