我继承了一个 SQL Server 数据库,该数据库有一个主键名为 RecordID 的表。表定义和外键定义如下:
CREATE TABLE [dbo].[MyTable](
[RecordId] [int] IDENTITY(1,1) NOT NULL,
[FileName] [nvarchar](255) NOT NULL,
[Record] [nvarchar](255) NOT NULL,
[ErrorDescription] [nvarchar](255) NULL,
[ProcessDate] [datetime] NOT NULL,
CONSTRAINT [PK_MyTable] PRIMARY KEY CLUSTERED
(
[RecordId] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, FILLFACTOR = 90) ON [PRIMARY]
) ON [PRIMARY]
GO
ALTER TABLE [dbo].[MyTable] WITH CHECK ADD CONSTRAINT [FK_MyTable_MyTable] FOREIGN KEY([RecordId])
REFERENCES [dbo].[MyTable] ([RecordId])
GO
ALTER TABLE [dbo].[MyTable] CHECK CONSTRAINT [FK_MyTable_MyTable]
GO
如果从同一个表中的不同字段引用的外键返回到允许层次结构的主键字段,我可以理解这一点,但在这种情况下,外键定义中的两个字段是完全相同的字段。这只是表和外键的原始定义中的错误吗?或者这有什么真正的优势?
提前感谢您的回复。