When using the Entity Framework, such as in an ASP.NET MVC application, you may find the model is empty after choosing database objects:
Adding new objects using “Add existing entities and relationships to this diagram by dragging them from the Model Browser” does not add the objects.
One cause for this is that a primary key has not been defined in the table or view you are trying to use in the model.
To resolve this, add a primary key to your table. Then, update the model:
Reselect the table/view and you will see it in your model.