sql - 值可以是主键和外键吗？

Question

我的 SQL Server 数据库中有以下表格。

Customer 是 User 的子类型，因此我引用了 Customer 到 User。

我还想将我的客户链接到我的预订。我想使用 Customer 表中的外键作为此关系的 PK。当我在 SQL Server 中写出这个时，我在“(userid)”下得到这个错误:

Invalid column 'userid'

我怎样才能建立这种关系？

Create table [dbo].[User]
(
    [id] int PRIMARY KEY IDENTITY (1,1) NOT NULL,
    [name] varchar(50) NOT NULL,
    [password] nvarchar(100) NOT NULL, 
)

Create table [dbo].[Customer]
(
    [userid] int FOREIGN KEY REFERENCES [dbo].[User](id) NOT NULL,
    [street] varchar(40) NOT NULL,
    [housenumber] varchar(10) NOT NULL,
    [postalcode] varchar(10) NOT NULL,
    [phonenumber] varchar(20) NOT NULL,
    [email] varchar(30) NOT NULL,
)

Create table [dbo].[Reservation]
(
    [id] int PRIMARY KEY IDENTITY (1,1) NOT NULL,
    [datum] date NOT NULL,
    [prijs] decimal NOT NULL,
    [levertijd] datetime NOT NULL,
    [ophaaltijd] datetime NOT NULL,
    [leverAdres] varchar(60) NOT NULL,
    [klantId] int FOREIGN KEY REFERENCES [dbo].[Customer](userid) NOT NULL
)

Answer 1

是的，这是可能的，试试这个

Create table [dbo].[Customer]
(
  [userid] int not null,
  [street] varchar(40) NOT NULL,
  [housenumber] varchar(10) NOT NULL,
  [postalcode] varchar(10) NOT NULL,
  [phonenumber] varchar(20) NOT NULL,
  [email] varchar(30) NOT NULL,

  constraint PK_UserID primary key ([userid]),
  constraint FK_Customer_User foreign key (userid) references [User] (id)
)

但我不得不说 userid 似乎是一个名为 Customer 的表的奇怪主键

我想要这样的东西:

Create table [dbo].[Customer]
(
  [CustomerID] int not null identity,
  [userid] int not null,
  [street] varchar(40) NOT NULL,
  [housenumber] varchar(10) NOT NULL,
  [postalcode] varchar(10) NOT NULL,
  [phonenumber] varchar(20) NOT NULL,
  [email] varchar(30) NOT NULL,

  constraint PK_CustomerID primary key ([CustomerID]),
  constraint FK_Customer_User foreign key (userid) references [User] (id)
)


Create table [dbo].[Reservation]
(
  [id] int PRIMARY KEY IDENTITY (1,1) NOT NULL,
  [datum] date NOT NULL,
  [prijs] decimal NOT NULL,
  [levertijd] datetime NOT NULL,
  [ophaaltijd] datetime NOT NULL,
  [leverAdres] varchar(60) NOT NULL,
  [klantId] int FOREIGN KEY REFERENCES [dbo].[Customer](customerid) NOT NULL

)