partial void DeleteClass(Class instance);
 partial void UpdateClass(Class instance);
		private void detach_Classes(Class entity)
		{
			this.SendPropertyChanging();
			entity.ClassType = null;
		}
 partial void InsertClass(Class instance);
		private void attach_Classes(Class entity)
		{
			this.SendPropertyChanging();
			entity.ClassType = this;
		}