You use the Entity Data Model Wizard to generate an Entity Data Model from an application database. You add a class named BaseEntity. You need to ensure that all entity classes extend BaseEntity and not ObjectEntity. You also need to ensure that your changes are not overwritten if you update the model from the database. Your effort should be minimal.
What should you do?

By default, the Entity Designer uses the EntityModelCodeGenerator custom tool to generate object-layer code. When you add a text template to a project, the Entity Designer can use the template to generate object-layer code instead of using the default custom tool. A template allows you to specify how generated classes will be defined.

If you use the default custom tool, the resulting objects will still inherit from EntityObject. Attempting to extend another class in a partial class definition will result in a compilation error.