Re: Is relational theory irrelevant? (was Re: Dreaming About Redesigning SQL)

From: Marshall Spight <mspight_at_dnai.com>
Date: Thu, 13 Nov 2003 03:10:17 GMT
Message-ID: <tCCsb.137796$ao4.438707@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.

Marshall Received on Wed Nov 12 2003 - 21:10:17 CST