将外键添加到组合键时出错

我在sql server中有两个表：

第一个表 Message_Child 有一个复合主键（MessageId，ChildId）

Message_Child (MessageId, ChildId, Date)

第二个表应包含 Message_Child 表的外键，因此我创建了两列：MessageId和ChildId .

Request (RequestId, MessageId, ChildId, type)

我创建了约束如下：

Alter table Request
ADD FOREIGN KEY (MessageId, ChildId) REFERENCES Message_Child(MessageId, ChildId);

但是我收到以下错误：

There are no primary or candidate keys in the referenced table 'Message_Child' that match the referencing column list in the foreign key 'FK_Request_534D60F1'.

Edit 添加代码：

Message_Child表：

CREATE TABLE [dbo].[Message_Child](
[ChildId] [int] NOT NULL,
[MessageId] [int] NOT NULL,
[Date] [datetime] NULL,
 CONSTRAINT [PK_Message_Child] PRIMARY KEY CLUSTERED 
(
[ChildId] ASC,
[MessageId] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF,      ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

GO

ALTER TABLE [dbo].[Message_Child]  WITH CHECK ADD  CONSTRAINT          [FK_Message_Child_Child_ChildId] FOREIGN KEY([ChildId])
REFERENCES [dbo].[Child] ([ChildId])
GO

ALTER TABLE [dbo].[Message_Child] CHECK CONSTRAINT [FK_Message_Child_Child_ChildId]
GO

ALTER TABLE [dbo].[Message_Child]  WITH CHECK ADD  CONSTRAINT     [FK_Message_Child_Message_MessageId] FOREIGN KEY([MessageId])
REFERENCES [dbo].[Message] ([MessageId])
GO

ALTER TABLE [dbo].[Message_Child] CHECK CONSTRAINT [FK_Message_Child_Message_MessageId]
GO

RequestQueue表：

CREATE TABLE [dbo].[RequestQueue](
[RequestQueueId] [int] IDENTITY(1,1) NOT NULL,
[PIN] [nvarchar](max) NULL,
[MessageId] [int] NULL,
[ChildId] [int] NULL,
 CONSTRAINT [PK_RequestQueue] PRIMARY KEY CLUSTERED 
(
[RequestQueueId] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF,   ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

GO

ALTER TABLE [dbo].[RequestQueue]  WITH CHECK ADD  CONSTRAINT   [FK_RequestQueue_MessageChildId] FOREIGN KEY([RequestQueueId])
REFERENCES [dbo].[RequestQueue] ([RequestQueueId])
GO

ALTER TABLE [dbo].[RequestQueue] CHECK CONSTRAINT [FK_RequestQueue_MessageChildId]
GO

然后我添加了这个：

Alter table [DayCareDB].[dbo].[RequestQueue]
ADD FOREIGN KEY (MessageId, ChildId) REFERENCES [DayCareDB].[dbo].[Message_Child](MessageId, ChildId);