Re: Peter Chen and Charles Bachman

From: Laconic2 <laconic2_at_comcast.net>
Date: Thu, 6 May 2004 08:23:27 -0400
Message-ID: <_a2dncSTBridswfdRVn-ig@comcast.com>

"Leandro Guimarães Faria Corsetti Dutra" <leandro_at_dutra.fastmail.fm> wrote in message news:pan.2004.05.05.21.36.57.495468_at_dutra.fastmail.fm...
> > Incomplete for what?
>
> For representing even the most basic constraints.

Nonsense. I can see you've never worked with an ER model.

Every ER model I've seen models relationships as either mandatory or optional, and as many-many many-one or one-one. Those are constraints. Most ER models classify attributes as single valued or multivalued. Some go further to list some attributes as optional.

You would do well to learn more about a tool before dismissing it. Received on Thu May 06 2004 - 07:23:27 CDT