DataSource Controls :: EntityFramework Base Class Inheritance?
Feb 11, 2010
I am having some issues with my base class inheritance. I am currently employing Table per Type Inheritance for the following tables:
Database:
Members Table
- Member ID (PK)
- First Name
- Last Name
- Email
- ...
Students Table
- Member ID (FK)
- Credits
- Notes
- ...
Instructors Table
- Member ID (FK)
- Biography
- Office Hours
- ...
My Entity Data Model defines "Member" as the base class for both Students and Instructors, since members can be both students as well as instructors simultaneously. The problem, however, occurs when I attempt to get a list of Members objects. Because the database contains members who are indeed students AND instructors, the following exception is thrown:
All objects in the EntitySet 'CountyCollegeEntities.BaseMembers' must have unique primary keys. However, an instance of type 'CountyCollege.NET.Administrator' and an instance of type 'CountyCollege.NET.Student' both have the same primary key value, 'EntitySet=BaseMembers;ID=10016'.
I am beginning to think that I made a mistake by building these classes to inherit from Member although it has been ideal up until this point. But before I start ripping up all my existing code to remove this inheritance, I thought I would see if anyone has any tricks that would make this work. Any advice as to either how I can get around this error or a more appropriate way to structure my classes would be very much appreciated.
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