SQL Server 将自动增量主键添加到现有表 [英] SQL Server add auto increment primary key to existing table

问题描述

作为标题，我有一个现有的表，它已经填充了 150000 条记录.我添加了一个 Id 列(当前为空).

As the title, I have an existing table which is already populated with 150000 records. I have added an Id column (which is currently null).

我假设我可以运行查询以使用增量数字填充此列，然后设置为主键并打开自动增量.这是正确的方法吗?如果是这样，我该如何填写初始数字?

I'm assuming I can run a query to fill this column with incremental numbers, and then set as primary key and turn on auto increment. Is this the correct way to proceed? And if so, how do I fill the initial numbers?

推荐答案

不 - 你必须反其道而行之:从一开始就将其添加为 INT IDENTITY - 它将是执行此操作时填充标识值:

No - you have to do it the other way around: add it right from the get go as INT IDENTITY - it will be filled with identity values when you do this:

ALTER TABLE dbo.YourTable
   ADD ID INT IDENTITY

然后你可以把它设为主键:

and then you can make it the primary key:

ALTER TABLE dbo.YourTable
   ADD CONSTRAINT PK_YourTable
   PRIMARY KEY(ID)

或者如果您更喜欢一步完成所有操作:

or if you prefer to do all in one step:

ALTER TABLE dbo.YourTable
   ADD ID INT IDENTITY
       CONSTRAINT PK_YourTable PRIMARY KEY CLUSTERED

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