如何更新 SQL Server 中的标识列

You can not update identity column.

与使用update语句处理其他列不同，SQL Server不允许更新标识列.

尽管有一些替代方案可以实现类似的需求.

• When Identity column value needs to be updated for new records

使用DBCC CHECKIDENT which checks the current identity value for the table and if it's needed, changes the identity value.

DBCC CHECKIDENT('tableName', RESEED, NEW_RESEED_VALUE)

• When Identity column value needs to be updated for existing records

使用IDENTITY_INSERT which allows explicit values to be inserted into the identity column of a table.

SET IDENTITY_INSERT YourTable {ON|OFF}

Example:

-- Set Identity insert on so that value can be inserted into this column
SET IDENTITY_INSERT YourTable ON
GO
-- Insert the record which you want to update with new value in the identity column
INSERT INTO YourTable(IdentityCol, otherCol) VALUES(13,'myValue')
GO
-- Delete the old row of which you have inserted a copy (above) (make sure about FK's)
DELETE FROM YourTable WHERE ID=3
GO
--Now set the idenetity_insert OFF to back to the previous track
SET IDENTITY_INSERT YourTable OFF