title: Entity Framework 4.0 Model First inheritance is lost after updating model from database
body: <p>In my application I'm using Entity Framework 4.0 Model First.
  I have several tables that implement inheritance, like <code>Product</code> as a basetable and <code>SpecificProduct</code> that inherits from Product. </p>
  
  <p>The inheritance is visible in the edmx file. To initially set up the database, I rightclick on the designer and select "Generate Database from Model", which generates an SQL create script.</p>
  
  <p>Let's assume I do some changes in the SQL database to the <code>SpecificProduct</code> table and want to upgrade the model. Obviously I'd delete the table <code>SpecificProduct</code> from my edmx file and I'd rightclick on the edmx designer and select "Update Model from Database".<br>
  This results in the inheritance between <code>Product</code> and <code>SpecificProduct</code> being lost. Instead of the inheritance I do have a 1 to 0..1 relationship and the primary key of <code>Product</code> is now also a column of <code>SpecificProduct</code>.<br>
  This is actually not the way I want it to be, because my project won't build anymore, because my code relies on the inheritance being available.</p>
  
  <p>I can manually fix this in the designer file by deleting the inserted primary key column into <code>SpecificProduct</code>, deleting the new 1 to 0..1 relationship, and inserting the inheritance in the edmx designer, again.<br>
  Ain't there a way to do this automatically?</p>
  
  <p>Or is this simply a limition of the Model First attempt, that I wasn't aware of (and wouldn't choose again, if this really is a limitation)?</p>