ADO.NET Entity Framework: Update Wizard will not add tables

Question

I added a new ADO.Net Entity Data Model into my project and used the Update Wizard to add tables into the model. Five of the selected tables were added to the design surface. Two other tables will not add. I select them in the wizard and click Finish, yet they never show up on the design surface.

Is this a bug, or are there some situations where a table cannot be added to the model (by design)?

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UPDATE: The XML (*.edmx) reveals the problem.

<!--Errors Found During Generation:
warning 6013: The table/view 'FooBar.dbo.Roles' does not 
have a primary key defined and no valid primary key could be inferred. 
This table/view has been excluded. To use the entity you will need to 
review your schema, add the correct keys and uncomment it.-->
<!--<EntityType Name="Roles">
    <Property Name="role_id" Type="decimal" />
    <Property Name="role_desc" Type="nvarchar" MaxLength="30" />
</EntityType>-->

Answer 1

The design surface is different from the entity model. It is possible to have a table in the mapping in your EDMX which does not appear on the design surface. View the file as XML to see if this is the case. In this case, the Update Wizard will not allow you to re-add the tables, since they are already part of the entity model. So, generally speaking, the Update Wizard knows more about your entity model than it does about the design surface, per se.

I don't think that's exactly the situation you're in, but it should give you the general idea for the solution: go into the XML and look for references to the tables in question.