Re: Why is "group by" obligatory in SQL?
Date: Fri, 24 Jul 2009 10:20:10 -0700 (PDT)
> I would say that the 'constraint problem' hasn't even been defined.
Not exactly I would not quite formulate it that way either.
I would rather say that the constraining problem has not been *formalized* to allow effective inferences within a Turing complete machine.
> Date took some baby steps by trying to classify different kinds of
> constraints. But sometimes such baby steps obscure the forest.
> Normalization is very much about information structure and I think it
> would be more practical to try to formalize the scope of constraints.
> If that could be done, then perhaps the constant question of 'where'
> constraints should be applied, eg., application or dbms would be
> clearer. (I don't believe the question is as obvious as many RT
> advocates suggest, there is more to it than trying to make sure the dbms
> is authoritative.)
I do have a few responses based on subtyping but nobody wants to hear them.
> > I have been working on that for a full decade and made fundamental
> > discoveries that not only applies to ra but also to computing. Just
> > no time to publish a book about it.
> >> - is the ultimate interface a program that it is in effect a relation?
> > Precisely. My point is that *only* a computing model can bring a
> > response to such question and that such question is orthogonal to RM.
Received on Fri Jul 24 2009 - 19:20:10 CEST