Re: Is relational theory irrelevant? (was Re: Dreaming About Redesigning SQL)
From: Marshall Spight <mspight_at_dnai.com>
Date: Wed, 12 Nov 2003 16:31:50 GMT
Message-ID: <Vftsb.179962$HS4.1498393_at_attbi_s01>
> Relations have no order. The values in relations have order. An ordered
> structure, like an array for instance, involves physical order.
Date: Wed, 12 Nov 2003 16:31:50 GMT
Message-ID: <Vftsb.179962$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?
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.
Marshall Received on Wed Nov 12 2003 - 17:31:50 CET