Re: 2 unique vals
From: Joe \ <joe_at_bftsi0.UUCP>
Date: Mon, 5 Jan 2004 11:44:00 -0800
Message-ID: <1073331846.432329_at_news-1.nethere.net>
Date: Mon, 5 Jan 2004 11:44:00 -0800
Message-ID: <1073331846.432329_at_news-1.nethere.net>
"shannon" <shannon_at_nolunchmeat.com> wrote in message <news:btbsju$2nb$03$2_at_news.t-online.com>...
> in the construction of an ERD, how do we proceed when an Entity has two
> attributes with unique values?
A relation can have more than one candidate key, just as a key can be on more than one attribute, no problem. Any problems come from brain-dead ERD tools or brain-damaged DBMS products.
-- Joe Foster <mailto:jlfoster%40znet.com> "Regged" again? <http://www.xenu.net/> WARNING: I cannot be held responsible for the above They're coming to because my cats have apparently learned to type. take me away, ha ha!Received on Mon Jan 05 2004 - 20:44:00 CET