I am using Visio for EA that came with VS.NET 2003. I am a novice ORM
modeler, and I am confused between what I see in the round-trip
between the ORM Concept and Logical Model.

I have a User object and a Role object. I pull them from the Object
types view onto my page and pull a predicate from the ORM source
shapes. I connect them up, stating that a User can have 0+ Roles and
Roles can have 0+ Users. However, I don't understand how to describe
how that relationship has Active and Inactive Dates, so I go to my
logical model, build my project and see a table created that has the
two keys for those objects as a composite primary key. I change it so
that it has its own primary key and that those keys are required, and
add my active/inactive dates. Pushing it back to the ORM model, I see
a new object (UserRole), along with the new value objects.

Here's my problem:
1. It appears that it is saying that I should have thought of UserRole
as an object to begin with. However, my understanding of ORM is that
I should NOT think of Table=Entity and Field=Value. Where is my wrong
thinking?

2. What I REALLY want is a restraint that says that I can have only
ONE combination of User and Role for any datepoint (respecting the
Active/Inactive dates). I understand that I cannot do that in ER and
have to rely on triggers on my DB. Is there any way to express that
in ORM?

Thank you for your patience.

Kevin Nechodom
University of Utah