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Asked: 2026-05-26T18:00:35+00:00

I’m working on a C# WPF app with a MySQL backend using Entity Data

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I’m working on a C# WPF app with a MySQL backend using Entity Data Model in VS2010 (.NET 4). I have the following simple test database schema (ignore StudentCourse.Grade for now):

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Students are assigned to courses with a many-to-many relationship via a connecting table. In EDM this is represented as two entities linked by an association mapped to the connecting table:

enter image description here

So far so good.
Now let’s say that each student gets a final grade for each course he/she takes which I’ve stored in the StudentCourse table as Grade. My problems is somehow getting the grade in the EDM. I’ve tried creating a new StudentCourse entity mapped to the StudentCourse table but it’s set to read-only because it has no id. Adding an id to the table causes Visual Studio to whine because the id field is not mapped in the association(which I don’t understand at all).

How is a relationship like this mapped in EDM? I’m open to changing the database schema if need be.

Edit in reply to Ucodia:
I don’t know. As far as UI goes, grades should be easily accessible for a student or for a course. I’m open to suggestions.

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1 Answer

  1. Editorial Team

    You need to add Grade to the link table and delete the many-to-many relationship. Then regenerate the model from the database. You will find that the StudentCourse table will show in the EDM. When there are additional fields in the link table, the link table will appear in the model.

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