How to reference two tables in Visual Studio 2012 by adding foreign key?

问题

I have a problem adding a foreign key to a table column. My tables look this way. I need to reference ContactOwnerId from Contact table to UserId in UserProfile table

CREATE TABLE [dbo].[Contacts] (
    [ContactId] INT            IDENTITY (1, 1) NOT NULL,
    [ContactOwnerId]    INT            NOT NULL,
    [FirstName] NVARCHAR (MAX) NOT NULL,
    [LastName]  NVARCHAR (MAX) NOT NULL,
    [Address]   NVARCHAR (MAX) NOT NULL,
    [City]      NVARCHAR (MAX) NOT NULL,
    [Phone]     NVARCHAR (MAX) NOT NULL,
    [Email]     NVARCHAR (MAX) NOT NULL,
    CONSTRAINT [PK_dbo.Contacts] PRIMARY KEY CLUSTERED ([ContactId] ASC), 
    CONSTRAINT [FK_Contacts_UserProfile] FOREIGN KEY ([UserId]) REFERENCES [Contacts]([ContactOwnerId])
);

CREATE TABLE [dbo].[UserProfile] (
    [UserId]   INT           IDENTITY (1, 1) NOT NULL,
    [UserName] NVARCHAR (56) NOT NULL,
    PRIMARY KEY CLUSTERED ([UserId] ASC),
    UNIQUE NONCLUSTERED ([UserName] ASC)
);

I added a foreign key, but it seems, not right, because UserId is highlighted, giving error:

SQL71501 :: Foreign Key: [dbo].[FK_Contacts_UserProfile] has an unresolved reference to Column [dbo].[Contacts].[UserId].
SQL71516 :: The referenced table '[dbo].[Contacts]' contains no primary or candidate keys that match the referencing column list in the foreign key. If the referenced column is a computed column, it should be persisted.

How do I correctly reference these two tables? Thanks in advance.

EDIT I did like sgeddes said. But I get an error, when I try to create a contact. The INSERT statement conflicted with the FOREIGN KEY constraint "FK_Contacts_UserProfile". The conflict occurred in database "ContactAppContext", table "dbo.UserProfile", column 'UserId'. The statement has been terminated.

If I remove a foreign key I get no error.

What I want to achieve is, when a user creates contacts, his Id(UserId) could associate with ContactOwnerId, so that contacts could relate to one specific user.

回答1:

Since ContactOwnerId in the Contact table should be the FOREIGN KEY, you need to specify that in your CONSTRAINT instead of UserId.

I think this is what you're trying to do:

CREATE TABLE [dbo].[UserProfile] (
    [UserId]   INT           IDENTITY (1, 1) NOT NULL,
    [UserName] NVARCHAR (56) NOT NULL,
    PRIMARY KEY CLUSTERED ([UserId] ASC),
    UNIQUE NONCLUSTERED ([UserName] ASC)
);

CREATE TABLE [dbo].[Contacts] (
    [ContactId] INT            IDENTITY (1, 1) NOT NULL,
    [ContactOwnerId]    INT            NOT NULL,
    [FirstName] NVARCHAR (MAX) NOT NULL,
    [LastName]  NVARCHAR (MAX) NOT NULL,
    [Address]   NVARCHAR (MAX) NOT NULL,
    [City]      NVARCHAR (MAX) NOT NULL,
    [Phone]     NVARCHAR (MAX) NOT NULL,
    [Email]     NVARCHAR (MAX) NOT NULL,
    CONSTRAINT [PK_dbo.Contacts] PRIMARY KEY CLUSTERED ([ContactId] ASC), 
    CONSTRAINT [FK_Contacts_UserProfile] FOREIGN KEY ([ContactOwnerId]) REFERENCES [UserProfile]([UserId])
);

The problem was with the last line. You need to reference the column from the Contacts table first, and then point to your UserProfile table. You had that backwards.

Here's a SQL Fiddle

Here's some documentation/examples for creating FOREIGN KEY CONSTRAINTS:

http://msdn.microsoft.com/en-us/library/aa258255(v=sql.80).aspx

来源：https://stackoverflow.com/questions/16751000/how-to-reference-two-tables-in-visual-studio-2012-by-adding-foreign-key

标签

sql

database

tsql

foreign-keys