Re: The IDS, the EDS and the DBMS
Date: Sun, 05 Sep 2004 02:34:51 GMT
Message-ID: <fXu_c.31617$3l3.28197_at_attbi_s03>
"mAsterdam" <mAsterdam_at_vrijdag.org> wrote in message news:41397886$0$78753$e4fe514c_at_news.xs4all.nl...
> Marshall Spight wrote:
>
> > Uh, sorry for being unclear. I mean "object-relational mapping." You
> > know, those million-and-one projects on sourceforge to provide you
> > with an object-based interface to your relational data, which comes
> > merely at the cost of crippling the kinds of queries you can make.
>
> Thank you for clearing that up. My guess was wrong, after all.
> Your statement becomes more interesting.
>
> Why are these object-relational mapping projects bogus?
> Is it because bridging the impedance mismatch is not a
> worthwhile quest, is it because it it impossible or
> just because none of these projects has done a good
> job at it yet?
I would say rather that attempts to bridge the impedance mismatch are trying to answer the wrong question. Despite my background as an OO coder, I am convinced that the power and generality of the OO model is not up to the level of the relational model. Thus, any attempt to wrap relational in OO is *necessarily* going to have less expressive power than the unwrapped plain relational model.
Although I am generally favorable towards D&D and TTM, I don't consider that they've gone far enough. They are absolutely correct in identifying the lame type systems of today's RDBMS products as being a significant hindrance, but their proposed language, while advanced in relational features, completely ignores everything else that's happened in the last 30 years in programming languages and type theory. It is like a variant of Fortran with highly developed relational features.
> Trade offs are to be expected.
Expected, yes, but are they required? I myself am not big on compromise; I want it all. I want the full power of the relational model, along with important and/or modern language features such as type inference, parametric polymorphism, first-class functions, partial evaluation, etc.
Marshall Received on Sun Sep 05 2004 - 04:34:51 CEST