Re: many to many relationship
Date: Wed, 12 Mar 2003 09:42:57 -0500
I agree with you. Anyway, even on an ERD (depending on notation), you can add attributes to this relationship.
"Bernard Peek" <bap_at_shrdlu.com> wrote in message
> In message <b4b321$1vdtf6$1_at_ID-114862.news.dfncis.de>, Alan
> <alan_at_erols.com> writes
> >Enrollment is not hidden in an ERD (which is a conceptual model) - it
> >as a diamond with M:N cardinality. Can't draw it here, but in text:
> That depends on your notation. When I draw up an ERD the enrolment
> entity would appear just like any other entity. As I said earlier,
> link-entities sometimes evolve into important parts of the logical
> model. Enrolment might have other attributes that could be important.
> For instance is it necessary to record the enrolment date?
> Bernard Peek
> www.diversebooks.com: SF & Computing book reviews and more.....
> In search of cognoscenti
Received on Wed Mar 12 2003 - 15:42:57 CET