A statement on dbdebunk.
Date: 18 Aug 2006 06:35:57 -0700
Message-ID: <1155908157.017108.118740_at_75g2000cwc.googlegroups.com>
One of the last posts on dbdebunk ("On conceptual modeling and database design") included the following :
<quote>
· Conceptual model: informal business concepts
· Logical model: formal representation (as much semantics as a
· Physical model: implementation in hardware/software
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.
(enterprise-specific)
system is capable of "understanding") (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
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 ? Received on Fri Aug 18 2006 - 15:35:57 CEST