Entity Framework relies on primary keys with views and tables.  If you are trying to bring a view into dbContext, and the view does not have a primary key the following should help you out.  The schema object has to have primary key defined and it be set to not allow nulls (not-null).

The solution for me was to refashion my view definition using RowId like the following
This will create a non-null RowId for each row in the result.

SELECT ISNULL(ROW_NUMBER() OVER(ORDER BY P1), -1) 
AS RowID, P1 AS Code, P3, P2
FROM dbo.BigTable 
WHERE P1 IS NOT NULL

After you create the view take a look at the view definition within SQL Server Management Studio.  You should see that you have defined a column RowId which is non-null. 

This will satisfy Entity Framework and dbContext can now include a reference to these views or tables.