Re: Modeling question...

On Oct 24, 12:09 am, paul c <toledobythe..._at_oohay.ac> wrote:
> David BL wrote:
>
> ...
>
> > If the relational model is universally applicable, why don’t
> > programmers enter their programs as relations? ...
>
> That is one of the most fundamental questions. At the risk of sounding
> like I'm sloughing it off, I'd say the answer has to do with tedium and
> lies somewhere near the fact that we have shortcuts and shorthands to
> give equivalent results and our human situation, limitations in
> momentary perception such as our shallow mental stack.

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, anyone using the full power of the FOL does a lot more than calculate with known extensions of sets. Received on Fri Oct 24 2008 - 04:17:49 CEST