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

"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? Received on Thu Nov 13 2003 - 00:26:27 CET