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

From: Paul Vernon <paul.vernon_at_ukk.ibmm.comm>
Date: Mon, 24 Feb 2003 19:16:43 -0000
Message-ID: <b3dr5r$sss$>

"Bob Badour" <> wrote in message news:zst6a.297$
> > Let me put it this way. If a type has 2 possiable representations, then
> > A) the number of values represented by PosRep1 must equal the number
> > of values represented by PosRep2
> > B) each value represented by PosRep1 must 'map' to exactly one value
> > represented bt PosRep2, and versa.
> While desirable whenever possible and while certainly possible in an ideal
> 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? Some aspect of the world that it is not capturing? Is this not the whole point of Date's work:

  Theory IS Practical

With my addition: (otherwise the theory is broke)

Paul Vernon

Business Intelligence, IBM Global Services Received on Mon Feb 24 2003 - 20:16:43 CET

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