当然，可以创建一个到一个化合物（多个列）主键的外键关系。您没有向我们展示您正在使用的语句来尝试创建这种关系 - 它应该是这样的：

  ALTER TABLE dbo.Content 
 ADD CONSTRAINT FK_Content_Libraries 
 FOREIGN KEY（LibraryID，Application）
 REFERENCES dbo.Libraries（ID，Application）
 

这就是你正在使用的？如果（ID，Application）确实是 dbo.Libraries 上的主键， p>

Luk：只要检查一下 - 你可以在你的数据库中运行这个语句并且报告输出结果是什么？

 选择
 tc.TABLE_NAME，
 tc.CONSTRAINT_NAME，
 ccu.COLUMN_NAME 
 FROM 
 INFORMATION_SCHEMA.TABLE_CONSTRAINTS tc 
 INNER JOIN 
 INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE ccu 
 ON ccu.TABLE_NAME = tc.TABLE_NAME AND ccu.CONSTRAINT_NAME = tc.CONSTRAINT_NAME 
 WHERE 
 tc.TABLE_NAME IN（'Libraries'，'内容'）
 

This question is pretty much similar to this one, but for SQL Server 2005 :

I have 2 tables in my database:

--'#' denotes the primary key
[Libraries]
#ID   #Application  Name
 1     MyApp        Title 1
 2     MyApp        Title 2


[Content]
#ID   Application  LibraryID  Content
 10    MyApp       1          xxx
 11    MyApp       1          yyy

(the database is obviously much more complex and having this double key makes sense)

Each library is identified by its unique ID and Application name. I'm trying to ensure that each content is properly referencing an existing library.

When creating the constraint (using the Wizard) as

Primary key table            Foreign key table
[Libraries]                  [Content]
ID                  --->     LibraryID
Application         --->     Application

I have the following error:

The columns in table 'Libraries' do not match an existing primary key or UNIQUE constraint

Do you have any idea of what is going on? and if it's possible at all using SQL Server? (I can't modify the [Library] table at all)

Thanks a lot for your help!

Of course it's possible to create a foreign key relationship to a compound (more than one column) primary key. You didn't show us the statement you're using to try and create that relationship - it should be something like:

ALTER TABLE dbo.Content
   ADD CONSTRAINT FK_Content_Libraries
   FOREIGN KEY(LibraryID, Application)
   REFERENCES dbo.Libraries(ID, Application)

Is that what you're using?? If (ID, Application) is indeed the primary key on dbo.Libraries, this statement should definitely work.

Luk: just to check - can you run this statement in your database and report back what the output is??

SELECT
    tc.TABLE_NAME,
    tc.CONSTRAINT_NAME, 
    ccu.COLUMN_NAME
FROM 
    INFORMATION_SCHEMA.TABLE_CONSTRAINTS tc
INNER JOIN 
    INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE ccu 
      ON ccu.TABLE_NAME = tc.TABLE_NAME AND ccu.CONSTRAINT_NAME = tc.CONSTRAINT_NAME
WHERE
    tc.TABLE_NAME IN ('Libraries', 'Content')