SQL Server 将列转换为标识列 [英] SQL Server convert column to an identity column

问题描述

我使用的是 SQL Server 2008.一个 int 列我用作主键而不是标识列(其值将自动增加 1).我想将此列转换为标识列.有什么解决办法吗?

I am using SQL Server 2008. One int column I used as primary key but not identity column (whose value will be increased by 1 automatically). I want to convert this column to identity column. Any solutions?

提前致谢，乔治

推荐答案

很遗憾，您无法将现有表上的字段更改为 IDENTITY.

Unfortunately, you cannot change a field to IDENTITY on an existing table.

你应该:

• 使用 IDENTITY 字段创建一个新表
• 为新表发出SET IDENTITY_INSERT ON
• 将数据插入到新表中
• 为新表发出SET IDENTITY_INSERT OFF
• 放下旧桌子
• 将新表重命名为旧名称.

您可以使用 SSMS 更改字段类型，它会在幕后为您完成所有这些.

You can use SSMS to change the field type, it will do all this for you behind the scenes.

这是一个示例表:

CREATE TABLE plain (id INT NOT NULL PRIMARY KEY)

INSERT
INTO    plain
VALUES  (1000)

和SSMS生成的脚本:

SET ANSI_PADDING ON
SET ANSI_WARNINGS ON
COMMIT
BEGIN TRANSACTION
GO
CREATE TABLE dbo.Tmp_plain
    (
    id int NOT NULL IDENTITY (1, 1)
    )  ON [PRIMARY]
GO
ALTER TABLE dbo.Tmp_plain SET (LOCK_ESCALATION = TABLE)
GO
SET IDENTITY_INSERT dbo.Tmp_plain ON
GO
IF EXISTS(SELECT * FROM dbo.plain)
     EXEC('INSERT INTO dbo.Tmp_plain (id)
        SELECT id FROM dbo.plain WITH (HOLDLOCK TABLOCKX)')
GO
SET IDENTITY_INSERT dbo.Tmp_plain OFF
GO
DROP TABLE dbo.plain
GO
EXECUTE sp_rename N'dbo.Tmp_plain', N'plain', 'OBJECT' 
GO
ALTER TABLE dbo.plain ADD CONSTRAINT
    PK__plain__3213E83F1A609306 PRIMARY KEY CLUSTERED 
    (
    id
    ) WITH( STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]

GO
COMMIT

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