Re: Dreaming About Redesigning SQL

bbadour_at_golden.net (Bob Badour) wrote in message news:<cd3b3cf.0310081652.469b1d9d_at_posting.google.com>...
> paul_geoffrey_brown_at_yahoo.com (Paul G. Brown) wrote in message news:<57da7b56.0310080006.47b550a9_at_posting.google.com>...
> > Lee Fesperman <firstsql_at_ix.netcom.com> wrote in message news:<3F833025.76A6_at_ix.netcom.com>...
> > > Jan Hidders wrote:
> > > >
> > > > Seun Osewa wrote:
> > > > > I would also like to know the classical arguments against the network
> > > > > model or other "pointer based" models. The only things I know are
> > > > > that:
> > > > >
> > > > > ** using pointers to positions in memory or disk can be messy when
> > > > > data has to be moved around. But then is seems there are several
> > > > > simple ways to solve this, e.g. what I can only call "logical
> > > > > pointers".
> > > >
> > > > Correct. There's absolutely no reason to believe that you cannot have
> > > > data independence with logical pointer or references. I would however
> > > > argue that allowing entities without representable keys is not a good idea.
> > >
> > > Incorrect. Even though you call them 'logical' pointers, they are still physical
> > > artifacts and have no place in a truly logical view of the database. Databases are about
> > > data, and pointers are not data (or meta-data).
> >
> > Erm . .
> >
> > What's 'physical' about this?
>
> Retrieval implies a physical operation, but a name is just a name
> after all. Having two attributes called name in a single structure
> requires physical location to disambiguate.

  Trouble with the old reading comprehension again, eh Bob?

  Have another look at what I typed. See the semi-colon? Two relations. Two   "structures", the attributes of which are unambiguous.

> > RELATION Dept ( Id Dept_Id KEY, Name String );
> > RELATION Emp ( Id Emp_Id KEY, Dept REF(Dept),
> > Name PersonName, Salary Money );
> >
> > RETRIEVE E.Name, DEREF(E.Dept).Name FROM Emp E;
> >
> > RETRIEVE E.Name FROM Emp E, Dept D
> > WHERE DEREF(E.Dept).Id = E.Id AND D.Name = 'shoe';
>
> Whether physical or not physical, the pointer is a superfluous
> structural element. Other than increasing complexity, what purpose
> does it serve?

    None. But that's not the point. Pleas read the carefully quoted text     from the previous posts.

    Where do I sign up to get back into your twit-filter?

    KR

              Pb Received on Thu Oct 09 2003 - 08:28:29 CEST