private void detach_Question_categories(Question_category entity)
		{
			this.SendPropertyChanging();
			entity.Category = null;
		}
 partial void DeleteQuestion_category(Question_category instance);
 partial void InsertQuestion_category(Question_category instance);
 partial void UpdateQuestion_category(Question_category instance);
		private void attach_Question_categories(Question_category entity)
		{
			this.SendPropertyChanging();
			entity.Question = this;
		}