Re: In an RDBMS, what does "Data" mean?

"Anthony W. Youngman" <wol_at_thewolery.demon.co.uk> wrote in message news:8jbIDPPhC7xAFwHy_at_thewolery.demon.co.uk...
> In message <lgGxc.6818$eP2.1437_at_newssvr32.news.prodigy.com>, Eric Kaun
> <ekaun_at_yahoo.com> writes
> >And as stated elsewhere, those aren't axioms anyway... he used the word
> >"representation", and the context fully suggests that he's not
correlating
> >it with the real world.
> >
> I know. After writing that I thought rather more about what C&D's twelve
> rules actually are. And that they don't seem to contain any axioms at
> all.
>
> Which leads to the conclusion that relational theory is axiom-free.
> Which means that it cannot be a valid model.

Some possibilities (I'm running too short on time to explore them): - The axioms may be simply implicit in his rules - What are MV's axioms? If it has them, then we could map at least some of them to relational (since there are commonalities)

> Which means that its
> application to the real world has no basis in anything whatsoever.

Maybe, but again, what sort of data model would have axioms? I'm not sure this is possible... and if it is, again, relational would somewhat-similar ones. Surely there's at least a partial homomorphism between data models?

> Okay, I'm sure that the mathematicians who've built on it have fleshed
> out the fundamentals somewhat, but it certainly means that if your sole
> criteria for defining a "relational database" is that "it complies with
> C&D's 12 rules", then such a database has no grounding in formal logic
> whatsoever.

Mathematics requires axioms - does logic? I thought it was purely symbolic manipulation, which is defined for relational.

• erk