partial void DeleteInvoice(Invoice instance);
 partial void UpdateInvoice(Invoice instance);
		private void detach_Invoices(Invoice entity)
		{
			this.SendPropertyChanging();
			entity.Customer = null;
		}
 partial void InsertInvoice(Invoice instance);
		private void attach_Invoices(Invoice entity)
		{
			this.SendPropertyChanging();
			entity.Customer = this;
		}