Re: Is relational theory irrelevant? (was Re: Dreaming About Redesigning SQL)
From: Bob Badour <bbadour_at_golden.net>
Date: Wed, 12 Nov 2003 23:00:26 -0500
Message-ID: <74Odna8jef-Mny6iRVn-gQ_at_golden.net>
> > Ordered domains do have logical order. Relations have no order, but the
> > values in the relations have order.
> > > In fact, the same relation can participate in many orderings.
> >
> > How does that relate to the order of an ordered structure like an array
vs.
> > an unordered structure like a relation?
>
> It sounds like we are not in disagreement.
Date: Wed, 12 Nov 2003 23:00:26 -0500
Message-ID: <74Odna8jef-Mny6iRVn-gQ_at_golden.net>
"Marshall Spight" <mspight_at_dnai.com> wrote in message
news:tCCsb.137796$ao4.438707_at_attbi_s51...
> "Bob Badour" <bbadour_at_golden.net> wrote in message
news:COydnd-jwepVXC-iRVn-hQ_at_golden.net...
> > "Marshall Spight" <mspight_at_dnai.com> wrote in message
> > news:Vftsb.179962$HS4.1498393_at_attbi_s01...
> > > "Bob Badour" <bbadour_at_golden.net> wrote in message
> > news:VaWdndbrNqgr0y-iRVn-jg_at_golden.net...
> > > >
> > > > Relations have no order. The values in relations have order. An
ordered
> > > > structure, like an array for instance, involves physical order.
> > >
> > > Why? Why can't you have logical order?
> >
> > Ordered domains do have logical order. Relations have no order, but the
> > values in the relations have order.
> > > >> > >
> > > In fact, this is closer to what I understand of order in the
> > > math textbooks I read. An ordered relation is a pair:
> > >
> > > (relation, ordering function)
> > >
> > > How is that physical?
> > > In fact, the same relation can participate in many orderings.
> >
> > How does that relate to the order of an ordered structure like an array
vs.
> > an unordered structure like a relation?
>
> It sounds like we are not in disagreement.
I don't disagree. ;-)
Received on Thu Nov 13 2003 - 05:00:26 CET