如何解决检查项目是否链接不正确-这是“外键约束”的目的吗？
| 我目前正在使用SQLAzure。 我正在设置一个设计，其中每个用户都有多个地址 然后，当用户下订单时，我想将该订单链接到用户和两个地址。 所以我的表看起来像： 用户 ID 名称 等等 地址 ID UserId（外键） 街 等等 订购 ID UserId（外键） DeliveryAddressId（外键） BillingAddressId（外键） 等等 有没有一种方法可以在SQL Server中设置检查，以便用户在任何情况下（例如，通过入侵HTML POST）都无法提交带有未与所提交的UserId链接的AddressId的Order 。我已经在文档中查看了“外键约束”，但这似乎并不是我想要的。 对于尝试什么-或阅读哪些教程的任何建议，将不胜感激。解决方法
除了地址表中的主键（在ID上）之外，您还应该在（Id，UserId）上声明另一个键约束，即UNIQUE约束。
ALTER TABLE Address ADD CONSTRAINT UQ_Address_UserCheck UNIQUE (Id,UserID)
ALTER TABLE Order ADD CONSTRAINT
FK_Order_DeliveryAddress_UserCheck FOREIGN KEY (DeliveryAddressID,UserID)
references Address (Id,UserId)
create table Users (
UserID int IDENTITY(1,1) not null,Name varchar(30) not null,/* Other columns */
constraint PK_Users PRIMARY KEY (UserID),constraint UQ_User_Names UNIQUE (Name)
)
go
create table Addresses (
AddressID int IDENTITY(1,UserID int not null,Street varchar(35) not null,/* Other columns */
constraint PK_Addresses PRIMARY KEY (AddressID),constraint FK_Addresses_Users FOREIGN KEY (UserID) references Users (UserID),constraint UQ_Addresses_UserCheck UNIQUE (UserID,AddressID)
)
go
create table Orders (
OrderID int IDENTITY (1,DeliveryAddressID int not null,BillingAddressID int not null,/* Other columns - there may be other nullability concerns above */
constraint PK_Orders PRIMARY KEY (OrderID),constraint FK_Orders_Users FOREIGN KEY (UserID) references Users (UserID),constraint FK_Orders_DeliveryAddresses FOREIGN KEY (DeliveryAddressID) references Addresses (AddressID),constraint FK_Orders_BillingAddresses FOREIGN KEY (BillingAddressID) references Addresses (AddressID),/* Further constraints - ensure UserID -> AddressID match */
constraint FK_Orders_DeliveryAddress_UserCheck FOREIGN KEY (UserID,DeliveryAddressID) references Addresses (UserID,AddressID),constraint FK_Orders_BillingAddress_UserCheck FOREIGN KEY (UserID,BillingAddressID) references Addresses (UserID,AddressID)
)
declare @UID1 int
declare @UID2 int
declare @AID1_1 int
declare @AID1_2 int
declare @AID2_1 int
declare @AID2_2 int
insert into Users (Name)
select \'User1\'
set @UID1 = SCOPE_IDENTITY()
insert into Users (Name)
select \'User2\'
set @UID2 = SCOPE_IDENTITY()
insert into Addresses (UserID,Street)
select @UID1,\'Street1\'
set @AID1_1 = SCOPE_IDENTITY()
insert into Addresses (UserID,\'Street2\'
set @AID1_2 = SCOPE_IDENTITY()
insert into Addresses (UserID,Street)
select @UID2,\'Street1\'
set @AID2_1 = SCOPE_IDENTITY()
insert into Addresses (UserID,\'Street2\'
set @AID2_2 = SCOPE_IDENTITY()
insert into Orders (UserID,DeliveryAddressID,BillingAddressID)
select @UID1,@AID1_1,@AID1_2 union all
select @UID2,@AID2_1,@AID2_1
insert into Orders (UserID,@AID2_1
(1 row(s) affected)
(1 row(s) affected)
(1 row(s) affected)
(1 row(s) affected)
(1 row(s) affected)
(1 row(s) affected)
(2 row(s) affected)
Msg 547,Level 16,State 0,Line 31
The INSERT statement conflicted with the FOREIGN KEY constraint \"FK_Orders_BillingAddress_UserCheck\". The conflict occurred in database \"Test\",table \"dbo.Addresses\".
The statement has been terminated.
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