Re: Modeling question...

From: paul c <>
Date: Fri, 24 Oct 2008 08:27:11 GMT
Message-ID: <zFfMk.3904$fF3.494_at_edtnps83>

David BL wrote:
> I believe there is a simple answer: The relational approach implies
> the appearance of many abstract identifiers.
> [Side note: Marshall allows a relational approach to encompass
> extensive use of RVAs - even to the point where at each level in the
> hierarchy of a heavily nested composite value, a relation is only
> being used to represent the children of a given node. This avoids the
> need to introduce lots of abstract identifiers, but I don't agree with
> Marshall that such an approach should be called "relational". Of
> course if anyone really wants to call that relational then that's fine
> by me - after all it's just a word. My argument of course only
> applies when heavily nested RVAs are not being used]
> I think you may be discounting the importance of languages (or more
> specifically grammars) or the concept of a well formed formula. After
> all the First Order Logic (FOL) is formalised with the concept of a
> wff which is defined recursively. It seems wrong to assume that data
> management doesn't encompass recording wffs. It seems wrong to assume
> that wffs can be represented /naturally/ in the RM. While it's true
> that the RM/RA is closely associated with set theory and the FOL,

I guess I was trying to answer the wrong question, should have said that   I was thinking of relations in general, didn't mean to suggest that Codd's RM is anything more than a narrow application of relations aimed mechanical storage and manipulation of db's. Received on Fri Oct 24 2008 - 10:27:11 CEST

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