RE: Why Model Concepts? (Was RE: Object Role Modelling (ORM) or U MLor ??for designing Schemas)

["Bullard, Claude L (Len)" <clbullar@ingr.com>]

Excellent!  Thanks Ken for saving some of us a lot of 
time in the weeds of discourse. :-)

The first paper is right on.  The second is a little 
foggy but generally, good conceptual models, transform 
schedules, and smart cacheing go a long way to 
achieving reuse AND performance.

Len 
http://www.mp3.com/LenBullard

Ekam sat.h, Vipraah bahudhaa vadanti.
Daamyata. Datta. Dayadhvam.h


-----Original Message-----
From: Ken North [mailto:ken_north@compuserve.com]

Different perspectives (conceptual schema, physical schema, user view) were
defined in the 70s by the ANSI/X3/SPARC Study Group on Database Management
Systems.

This paper has an explanation:
http://www.nist.gov/sc4/wg_qc/wg10/current/n089/wg10n089.pdf

conceptual model: description of the content, the structure, the rules, and
behaviour in a universe of discourse

This paper discusses the advantages of physical data independence in a
hypermedia context:
http://www.dke.uni-linz.ac.at/research/publications/abstracts/Prue96c.html



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