创建SQL Server表关系的问题

Question

I have 2 tables.

First table:

create table abc
(
    AId  INT IDENTITY(1,1),
    Name NVARCHAR(50),
    EMP NVARCHAR(50)

    CONSTRAINT PK_abc PRIMARY KEY (AId, Name)
)

And second table as:

create table def
(
    AId  INT,
    Comment NVARCHAR(50)

    constraint FK_aid FOREIGN KEY (AId) references abc (AId)
)

This throws an error:

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

So I updated as:

create table def
(
    AId  INT,
    Name NVARCHAR(50),
    Comment NVARCHAR(50)

    constraint FK_AID FOREIGN KEY (AId, Name) references abc (AId, Name)
)

But this throws another error:

More than one key specified in column level FOREIGN KEY constraint, table 'def'.

Not sure what am I missing here.

---Updated----

Sorry for giving vague example. I was having difficulty in explaining my problem here. I have attached the screenshot of my problem. This show the eventual output that I am expecting by making join to 3 tables. Where the data of 3 tables is populated from an input form.

I have tried to provide in a clear way. Let me know if you need more inputs.

Attchment at: https://imgur.com/a/jfFS6

Thanks

Answer 1

You have an identity column. Use it as the primary key:

create table abc (
    AId  INT IDENTITY(1,1) PRIMARY KEY,
    Name NVARCHAR(50),
    EMP NVARCHAR(50)
);

create table def (
    AId  INT,
    Comment NVARCHAR(50)
    constraint FK_aid FOREIGN KEY (AId) references abc (AId)
);

Name should not be in the definition of the primary key.

Answer 2

Looks like you have to do it as a separate statement:

ALTER TABLE [dbo].[def]  WITH CHECK ADD  CONSTRAINT [FK_def_abc] FOREIGN KEY([AId], [Name])
REFERENCES [dbo].[abc] ([AId], [Name])
GO

ALTER TABLE [dbo].[def] CHECK CONSTRAINT [FK_def_abc]
GO  

But you still should NOT do that. Identity is unique and it alone should be used as primary key.