 GO --添加 订单 外键
 ALTER TABLE [Orders]  WITH CHECK ADD  CONSTRAINT [FK_Orders_Customers] FOREIGN KEY([CustomerID])
		REFERENCES [Customers] ([CustomerID]) 
 GO --约束检查
 ALTER TABLE [Orders] CHECK CONSTRAINT [FK_Orders_Customers] 
 

 GO --添加 订单 外键
 ALTER TABLE [Orders]  WITH CHECK ADD  CONSTRAINT [FK_Orders_Employees] FOREIGN KEY([EmployeeID])
		REFERENCES [Employees] ([EmployeeID]) 
 GO --约束检查
 ALTER TABLE [Orders] CHECK CONSTRAINT [FK_Orders_Employees] 
 

 GO --添加 订单 外键
 ALTER TABLE [Orders]  WITH CHECK ADD  CONSTRAINT [FK_Orders_Shippers] FOREIGN KEY([ShipperID])
		REFERENCES [Shippers] ([ShipperID]) 
 GO --约束检查
 ALTER TABLE [Orders] CHECK CONSTRAINT [FK_Orders_Shippers] 
 

