Re: Extending my question. Was: The relational model and relational algebra - why did SQL become the industry standard?

From: Bob Badour <>
Date: Tue, 25 Feb 2003 02:32:36 -0500
Message-ID: <mnF6a.332$>

"Paul Vernon" <paul.vernon_at_ukk.ibmm.comm> wrote in message news:b3dr5r$sss$
> "Bob Badour" <> wrote in message
> news:zst6a.297$
> > > Let me put it this way. If a type has 2 possiable representations,
> > > A) the number of values represented by PosRep1 must equal the
> > > of values represented by PosRep2
> > > B) each value represented by PosRep1 must 'map' to exactly one
> > > represented bt PosRep2, and versa.
> >
> > While desirable whenever possible and while certainly possible in an
> > machine, I do not require this of physical implementations.
> Yes and that is my worry. I'm not comfortable with such a fudge. If the
> logical model cannot be implemented correctly then is there not something
> wrong with the model?

First, I would disagree that the implementation is incorrect. Second, I would observe that a logical data model is an ideal abstraction. Third, I would observe that any flaw lies in the physical implementation and not the logical data model. Fourth and finally, I must ask: What other logical data model do you propose that addresses the specific issue of cartesian and polar coordinates and possible rounding in the internal physical representation?

> Some aspect of the world that it is not capturing?

After you demonstrate we live in an infinite and continuous universe, I'll get back to you.

> Is
> this not the whole point of Date's work:
> Theory IS Practical

In what way is it not practical?

> With my addition: (otherwise the theory is broke)
> Regards
> Paul Vernon
> Business Intelligence, IBM Global Services
Received on Tue Feb 25 2003 - 08:32:36 CET

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