Re: A statement on dbdebunk.

anith..._at_gmail.com wrote:
> Erwin wrote:
> > One of the last posts on dbdebunk ("On conceptual modeling and database
> > design") included the following :
> >
> > <quote>
> > My material is sound because unlike all the stuff floating in the
> > industry, the logical level is formal and the conceptual level was
> > developed to allow 1:1 mapping to it.
> >
> >
> >
> > · Conceptual model: informal business concepts
> > (enterprise-specific)
> >
> > · Logical model: formal representation (as much semantics as a
> > system is capable of "understanding") (enterprise-specific)
> >
> > · Physical model: implementation in hardware/software
> > (enterprise-specific)
> >
> > · Data model: A "formal mapping construct" to map conceptual to
> > logical models (universal theory of data)
> >
> > </quote>
> >
> > Note in particular :
> >
> > Conceptual model === INFORMAL
> > Logical model === FORMAL
> > Conceptual model "ALLOWS A 1:1 MAPPING" to the logical model
> >
> > Now, it seems to me that "allows a 1:1 mapping" means that there is
> > some kind of isomorphism between the things that are mapped in such
> > way.
> >
> > And the fact that some kind of isomorphism between two things can be
> > found, implies that any quality or property that holds/exists/is proven
> > for either of the things mapped, necessarily also holds/exists for the
> > other thing mapped.
> >
> > So if model X has the property of being formal in some sense, and model
> > Y is in some way isomorphic to model X, then it necessarily follows
> > that model Y is also formal in that same sense as model X is formal .
> >
> > So the statements quoted here, seem contradictory to me, if not
> > quackery.
> >
> > Anyone care to correct me on this, or comment in any other way ?
>
> Fabian has already explained it in his article "Something To Call One's
> Own" which seems to be in the zipped free archives in his site.
> http://www.dbdebunk.com/content2001.html
> For some of his relevant online references, see:
> http://www.inconcept.com/JCM/May2003/Pascal.html
> http://www.inconcept.com/JCM/October2003/Pascal.htm

These might be of interest too:
http://www.dbazine.com/ofinterest/oi-articles/pascal1 http://www.tdan.com/sms_issue28.htm Received on Fri Aug 18 2006 - 16:02:33 CEST