Re: Relational Lattice, what is it good for?
From: Marshall Spight <marshall.spight_at_gmail.com>
Date: 17 Feb 2006 15:55:49 -0800
Message-ID: <1140220549.287757.314640_at_f14g2000cwb.googlegroups.com>
Date: 17 Feb 2006 15:55:49 -0800
Message-ID: <1140220549.287757.314640_at_f14g2000cwb.googlegroups.com>
vc wrote:
> Marshall Spight wrote:
> [...]
>
> That does not make any obvious sense. What is '(a, b, ab)' ? Is it
> the union of sets of attributes [of their respective relations] or
> something else ? You did not define the expression.
Under Conventions, I wrote:
So '(a, b, ab)' contains all the attributes that are only in A, all the attributes that are only in B, and all the attributes that in in both A and B.
HTH Marshall Received on Sat Feb 18 2006 - 00:55:49 CET