ER Model - different answers for different join paths

From: Walton Chan <wchan1_at_rci.rogers.com>
Date: 1997/08/06
Message-ID: <01bca266$03790d00$83df020a@wchan1>#1/1

Ralph Kimball's book, 'The Data Warehouse Toolkit', indicated that one of the relational database myths was that there would be the same answer for different join paths chosen. In order words, depending on which tables you chose to join, the ER model will yield different answers, i.e. wrong answer.

Does it mean we can no longer trust our ER modeled relational database? Unfortunately, Ralph did not give any example of how this could happen. In the real life, I have not encounter such instance with those properly defined ER models.

Can anyone help me to understand the problem as Ralph stated (with examples)?
Thanks ... Received on Wed Aug 06 1997 - 00:00:00 CDT