Mapping from ORM to ER model

[mmm]

Hi everyone,

I tried to map from ORM diagram to ER model but I found that the constraint
I've set on ORM diagram is not mapped!

My facts and constraints are:

1. Student(IdStu) is in University(IdUni) (constraint: each student must be
in 1 univ)

2. Student practices Sport(IdSpo)

3. Student practices Art(IdArt)

The external mandatory constraint on facts 2 and 3 is: every student must
practice Sport or Art.

After mapping, 3 tables created are
1. Student(Student IDStu, Is in University IdUni),
2. Student practices Art(Student IdStu, Art),
3. Student practices Sport(Student IdStu, Sport IdSpo).

There's a relationship from the table "Student practices Art" to "Student"
and a relationship from the table "Student practices Sport" to "Student".

So the problem is this model does not tell us that every student must
practice Art or Sport!

Is it impossible to convert from ORM to ER with full information/constraints?

Thank you very much and awaiting for your reply.

 

[Scot Becker]

Unfortunately, not all ORM constraints get implemented in the ER model.
However, this one appears to be (it is when I generated it). In the database
model diagram, take a look at the code window (Database | View | Code).

If you double click on it, you will see a stored procedure generation
script. You will, however, need to "wire it up" by using that SP when saving
any related data, calling it from insert/update triggers on those tables,
etc.

Hope that helps,
Scot.
................................................
Scot Becker

Orthogonal Software
www.orthogonalsoftware.com

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