Re: Do Data Models Need to built on a Mathematical Concept?
From: Neo <neo55592_at_hotmail.com>
Date: 5 May 2003 19:55:58 -0700
Message-ID: <4b45d3ad.0305051855.7b49d351_at_posting.google.com>
Date: 5 May 2003 19:55:58 -0700
Message-ID: <4b45d3ad.0305051855.7b49d351_at_posting.google.com>
> In any case (b,j) is not A binary relation, it is composed OF two
> binary relations: b is directly related to A, and j is directly
> related to A, therfore, b and j are indirectly related but via A.
An error on my part, I was assuming AxA in which case a1 and a2 would be directly related to A and thus a1 and a2 are indirectly related.
Anyways, if I count relations instead of things, Schaum's definition
would basically be correct except it should be:
A = (a1, a2)
B = (b1, b2)
AxB = ((a1,b1), (a1,b2), (a2,b1), (a2,b2))
Then then elements of the set produced by AxB are examples (4 in this
case) of binary relations.
Received on Tue May 06 2003 - 04:55:58 CEST