How to create inheritance in linq to sql class with abstract class

I want to have an abstract class with 3 classes extending it which i need to save to a database using linq. I've made开发者_开发知识库 a table with all the attributes of the parent class and the 3 subclasses.

Can't figure out how to properly set this up in the OR designer.

When i set TimeRecord's Inheritance modifier to "abstract" i get the following error: error

OR Design

The GetTable() method tries to create an instance of your class which is abstract it can't do that
remove abstarct modifier from your class