private void detach_Customers(Customer entity)
		{
			this.SendPropertyChanging();
			entity.City = null;
		}
		private void attach_Customers(Customer entity)
		{
			this.SendPropertyChanging();
			entity.City = this;
		}
 partial void UpdateCustomer(Customer instance);
 partial void DeleteCustomer(Customer instance);
 partial void InsertCustomer(Customer instance);