You can do that in both run-time and design-time.
If you would like to do this in design time then you should write your artificial fields by hand in the app.config file. Once you are done just set the UpdateDatabase to true and rebuild. This will automatically create the required ddl script and update the database.
If you would like to use this in runtime, you should apply your artificial fields using the XML approach and use this code:
|ISchemaHandler schema = Database.Get("DatabaseConnection1").GetSchemaHandler();
This will create a ddl script and execute it against the database.
the Telerik team