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From: sakkinen@tukki.jyu.fi (Markku Sakkinen)
Newsgroups: comp.object,comp.databases
Subject: Re: Object Data Models and Manipulation Languages
Keywords: object-oriented data model query language
Message-ID: <3615@tukki.jyu.fi>
Date: 1 Mar 90 12:56:46 GMT
References: <1990Feb28.095810.15619@newcastle.ac.uk> <1466@inria.inria.fr>
Reply-To: sakkinen@jytko.jyu.fi (Markku Sakkinen)
Organization: University of Jyvaskyla, Finland
Lines: 49

In article <1466@inria.inria.fr> mark@bdblues.altair.fr writes:
>In article <1990Feb28.095810.15619@newcastle.ac.uk> B.J.King@newcastle.ac.uk (Brian King) writes:
> ...
>>1. is anyone aware of any consensus on object-oriented data models
>>   and query languages?
>
>The closest thing to a consensus can be found in D. Maier and S.
>Zdonik, eds., _Readings in Object-Oriented Database Systems_, Morgan
>Kaufman, 1990.  Read especially the first chapter on OODBMS
>fundamentals.

Now there is already paper that reflects a much more significant consensus:
"The object-oriented database manifesto" from the first international DOOD
(deductive and OO databases) conference, held in December in Kyoto.
There was in the previous posting (T. Mark Jones) a reference to another
paper in the same proceedings.

The compilation of Maier and Zdonik can be warmly recommended even to
those who have the original papers (in journals and conference proceedings)
available. The editors' introductory and summary chapters are concise
and helpful.

>> ...
>>3. is there a clear distinction between an object-oriented and semantic
>>   data model?
>
>A *clear* distinction?  Hahahahahahahahahaha......

Perhaps one could say that semantic models have mostly concentrated
on what Dittrich calls _structural_ object-orientation, and OOPL's
on _behavioural_ object-orientation.

The great divide probably goes between value-oriented (mostly relational)
and identity-oriented data models, as Ullman says in his "Principles
of Database and Knowledge-base Systems" (Vol. 1). Of course, extensions
of the relational model (and of relational DBMS's) can possibly provide
many of the features typically associated with OODBMS's. We may soon
have a situation similar to that when relational DB's came into vogue:
several vendors of DBMS's based on different data models (hierarchic,
restricted network, inverted files, ...) tried to make their products
look as relational as possible.

Markku Sakkinen
Department of Computer Science
University of Jyvaskyla (a's with umlauts)
Seminaarinkatu 15
SF-40100 Jyvaskyla (umlauts again)
Finland
          SAKKINEN@FINJYU.bitnet (alternative network address)