创建外键来复合主键

Question

我有两个表格- 教育人员和学院 ：

CREATE TABLE [dbo].[Educators]
(
    [UserId] [nvarchar](128) NOT NULL,
    [FacultyId] [smallint] NOT NULL,
    [InstitutionUserId] [nvarchar](128) NOT NULL,

    CONSTRAINT [PK_Educators] 
        PRIMARY KEY CLUSTERED ([UserId] ASC)
)

CREATE TABLE [dbo].[Faculties]
(
    [InstitutionUserId] [nvarchar](128) NOT NULL,
    [FacultyId] [smallint] NOT NULL,

    CONSTRAINT [PK_UserFaculties] 
        PRIMARY KEY CLUSTERED ([InstitutionUserId] ASC, [FacultyId] ASC)
)

表Faculties具有由两列（ InstitutionUserId和FacultyId ）组成的复合主键。 我在Educators表中也有相同的列。 我想将这两个表与一个外键链接在一起。

因此，这是我的查询：

ALTER TABLE [dbo].[Educators] WITH CHECK 
    ADD CONSTRAINT [FK_Educators_FacultyId_Faculties_FacultyId] 
    FOREIGN KEY ([FacultyId], [InstitutionUserId])
    REFERENCES [dbo].[Faculties] ([FacultyId], [InstitutionUserId])

但是我收到此错误消息：

消息1776，级别16，状态0，第7行
引用表'dbo.Faculties'中没有与外键'FK_Educators_FacultyId_Faculties_FacultyId'中的引用列列表匹配的主键或候选键。

消息1750，第16级，状态1，第7行
无法创建约束或索引。 请参阅先前的错误。

如何解决这个问题呢？

Answer 1

您的表及其约束看起来很好。 我唯一看到的问题是主键中列的顺序

CONSTRAINT [PK_UserFaculties] PRIMARY KEY CLUSTERED 
(
    [InstitutionUserId] ASC,
    [FacultyId] ASC
)

与您在外键约束中声明的顺序不同

ALTER TABLE [dbo].[Educators]  WITH CHECK ADD  CONSTRAINT [FK_Educators_FacultyId_Faculties_FacultyId] FOREIGN KEY([FacultyId], [InstitutionUserId])
REFERENCES [dbo].[Faculties] ([FacultyId], [InstitutionUserId])

尝试像这样更改外键声明中的列顺序：

ALTER TABLE [dbo].[Educators]  WITH CHECK ADD  CONSTRAINT [FK_Educators_FacultyId_Faculties_FacultyId] FOREIGN KEY([InstitutionUserId], [FacultyId])
REFERENCES [dbo].[Faculties] ([InstitutionUserId], [FacultyId])

Answer 2

密钥应与定义的顺序相同：

ALTER TABLE dbo.Educators
    ADD CONSTRAINT FK_Educators_FacultyId_Faculties_FacultyId
        FOREIGN KEY(InstitutionUserId, FacultyId)
            REFERENCES dbo.Faculties(InstitutionUserId, FacultyId);