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Home -> Community -> Usenet -> comp.databases.theory -> Re: Does Codd's view of a relational database differ from that ofDate&Darwin?[M.Gittens]

Re: Does Codd's view of a relational database differ from that ofDate&Darwin?[M.Gittens]

From: Jon Heggland <heggland_at_idi.ntnu.no>
Date: Thu, 23 Jun 2005 15:33:07 +0200
Message-ID: <MPG.1d247ec3f78858a59896ad@news.ntnu.no>


In article <tViue.127265$Xj7.7072901_at_phobos.telenet-ops.be>, jan.hidders_at_REMOVETHIS.pandora.be says...
> >>Jan Van den Bussche , Jan Paredaens, The expressive power structured
> >>values in pure OODB's (extended abstract), Proceedings of the tenth ACM
> >>SIGACT-SIGMOD-SIGART symposium on Principles of database systems,
> >>p.291-299, May 29-31, 1991, Denver, Colorado, United States
> >
> > I don't have access to such paper, but the OODB data model does not
> > exist. OODB's use the network approach.
>
> I didn't say the OODB data model, I said the *pure* OODB data model.
>
> The point of the paper is to show that on the leading conferences on
> database theory you can publish papers on the pure OODB data model and
> everybody will know what you are talking about. It is a wel-defined
> concept, there a a few different definitions but they only differ in
> minor points, it's well-understood, I know what it means and so do most
> researchers in the field, and people smarter than you and me publish
> papers about it. Describing that situation as "the concept does not
> exist" would be, well, slightly ridiculous.

Would that it were that simple. The same could be said about the "XML data model", yet well-known researchers are happily reinventing the square wheels of IMS and similar systems, apparently blissfully unaware of the history and fate of hierarchical databases. I recently reviewed a paper for VLDB which was quite scary in that regard---especially since another reviewer, a really *big* name, said it was the strongest he had reviewed.

I might agree that the model presented as a "pure object-oriented database model" in the paper you mentioned is slightly different from the (most common interpretations of the) network data model. (Note, however, that the paper talks of modelS, not THE pure OODB model.) The question is whether such models are different *enough* from the network model(s) to make it worthwhile to distinguish between them. The concept exists, but that in itself does not mean very much.

(Another point is the question of what "OO" in that context really means---the paper does not mention encapsulation, polymorphism or inheritance. What is an object?)

-- 
Jon
Received on Thu Jun 23 2005 - 08:33:07 CDT

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