Re: Principle of Orthogonal Design

From: Brian Selzer <brian_at_selzer-software.com>
Date: Thu, 07 Feb 2008 13:54:04 GMT
Message-ID: <04Eqj.7465$0o7.5640_at_newssvr13.news.prodigy.net>


"JOG" <jog_at_cs.nott.ac.uk> wrote in message news:c8bd75c2-5a4b-4456-8646-4ed912cc578b_at_i29g2000prf.googlegroups.com...
> On Feb 7, 11:21 am, "Brian Selzer" <br..._at_selzer-software.com> wrote:
>> [snip]
>> A join is not a constraint, is it?
>
> Now that's a very interesting question. Let me be polemic and say I
> think it is.

Interesting indeed. So, for example, the join of relations

P {A, B, C} and
Q{D, E, F, G}

yields a relation with the heading,

{A, B, C, D, E, F, G}.

Can you explain what is constrained by P JOIN Q? Received on Thu Feb 07 2008 - 14:54:04 CET

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