Union / set difference problem
From: Enrico Sanchez <enrico26_at_gotmail.com>
Date: Tue, 27 Nov 2001 22:14:09 -0000
Message-ID: <3c040fd8$1_3_at_mk-nntp-1.news.uk.worldonline.com>
Hi.
I am trying to solve the following problem within database theory:
Date: Tue, 27 Nov 2001 22:14:09 -0000
Message-ID: <3c040fd8$1_3_at_mk-nntp-1.news.uk.worldonline.com>
Hi.
I am trying to solve the following problem within database theory:
Decide if the following 2 statements are valid: 1) if A and B are superkeys for R then A U (B-A) is a superkey for R 2) the intersection of two (distinct) superkeys for R is always a candidate
key for RI'm lost. Can anyone give me a hint on how to solve this? Thanks. Enrico. Received on Tue Nov 27 2001 - 23:14:09 CET