Re: many to many relationship
Date: Fri, 7 Mar 2003 09:19:20 -0500
Don't confuse the conceptual model (ERD) with the physical model (realtional schema). An ERD models the business. It then gets translated into a physical model, which represents the implemented tables in a database.
If the business is modeled properly, and the proper mapping (translation) is done (and there _are_ rules to follow), then the resulting relational schema is almost always (99.9% of the time) in 3NF.
"Paul Vernon" <paul.vernon_at_ukk.ibmm.comm> wrote in message
> All of which is an argument against the usefulness of the ER model's
> many-to-many relationships idea. In this case, was the ER model clearer
> without an explicit 'enrollement' entity?
> Paul Vernon
> Business Intelligence, IBM Global Services
Received on Fri Mar 07 2003 - 15:19:20 CET