使用标题不同的表中的两个主键属性

Question

我获得了带有Function_ID {PK}的表“ Functions”，并且我想要另一个具有Hierarchy_ID {PK}的表“ Hierarchy”，它定义了函数的树结构，因此我需要功能表AS Parent_ID中的一个Function_ID和功能子ID AS Child。 我的问题是我如何使用另一个表中的两个主键将其一起作为外键

我正在使用SQL Server 2012和Management Studio

非常感谢

Answer 1

实际上，您只需要在Functions表中添加ParentFunction_ID列。
如果您的结构确实是一棵树，则不需要另一个表。
然后使ParentFunction_ID成为同一表函数的FK。
因此ParentFunction_ID（FK）将指向Function_ID（PK）。
具有ParentFunction_ID NULL的唯一记录将是树的根。

这是一些示例代码：

USE [test]
GO

SET ANSI_NULLS ON
GO

SET QUOTED_IDENTIFIER ON
GO

SET ANSI_PADDING ON
GO

CREATE TABLE [dbo].[Functions](
    [Function_ID] [int] IDENTITY(1,1) NOT NULL,
    [FunctionCode] [varchar](max) NULL,
    [ParentFunction_ID] [int] NULL,
 CONSTRAINT [PK_Functions] PRIMARY KEY CLUSTERED 
(
    [Function_ID] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

GO

SET ANSI_PADDING OFF
GO

ALTER TABLE [dbo].[Functions]  WITH CHECK ADD  CONSTRAINT [FK_Functions_Functions] FOREIGN KEY([ParentFunction_ID])
REFERENCES [dbo].[Functions] ([Function_ID])
GO

ALTER TABLE [dbo].[Functions] CHECK CONSTRAINT [FK_Functions_Functions]
GO

Answer 2

将功能表命名为功能表。 AFAIK使用
表名称的复数形式并不是一个好习惯。

因此，您可以执行此操作。

--- 1 ---    
SET ANSI_NULLS ON
GO

SET QUOTED_IDENTIFIER ON
GO

SET ANSI_PADDING ON
GO

CREATE TABLE [dbo].[Function](
    [Function_ID] [int] IDENTITY(1,1) NOT NULL,
    [FunctionCode] [varchar](max) NULL,
 CONSTRAINT [PK_Function] PRIMARY KEY CLUSTERED 
(
    [Function_ID] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

GO

SET ANSI_PADDING OFF
GO




--- 2 ---
SET ANSI_NULLS ON
GO

SET QUOTED_IDENTIFIER ON
GO

CREATE TABLE [dbo].[Hierarchy](
    [ID] [int] IDENTITY(1,1) NOT NULL,
    [ParentFunction_ID] [int] NULL,
    [ChildFunction_ID] [int] NULL,
 CONSTRAINT [PK_Hierarchy] PRIMARY KEY CLUSTERED 
(
    [ID] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

GO

ALTER TABLE [dbo].[Hierarchy]  WITH CHECK ADD  CONSTRAINT [FK_Hierarchy_Function] FOREIGN KEY([ParentFunction_ID])
REFERENCES [dbo].[Function] ([Function_ID])
GO

ALTER TABLE [dbo].[Hierarchy] CHECK CONSTRAINT [FK_Hierarchy_Function]
GO

ALTER TABLE [dbo].[Hierarchy]  WITH CHECK ADD  CONSTRAINT [FK_Hierarchy_Function1] FOREIGN KEY([ChildFunction_ID])
REFERENCES [dbo].[Function] ([Function_ID])
GO

ALTER TABLE [dbo].[Hierarchy] CHECK CONSTRAINT [FK_Hierarchy_Function1]
GO