How Can I Update an SQL Server Identity Column?

Fixing Inconsistencies in SQL Server Identity Column

Your concern regarding updating the identity column in SQL Server is a common issue. While it's crucial to understand that you cannot directly update identity columns like other table columns, SQL Server offers alternative solutions.

Alternatives for Modifying Identity Columns:

A. For New Records:

When only new records need to be updated, DBCC CHECKIDENT can be leveraged. This command verifies the current identity value and adjusts it, if necessary.

DBCC CHECKIDENT('tableName', RESEED, NEW_RESEED_VALUE)

B. For Existing Records:

For existing records, IDENTITY_INSERT allows explicit values to be inserted into the identity column.

SET IDENTITY_INSERT YourTable {ON|OFF}

Example:

To update the identity column for existing record 3 with the value 13:

-- Enable identity insertion
SET IDENTITY_INSERT YourTable ON

-- Insert copy with desired value
INSERT INTO YourTable(IdentityCol, otherCol) VALUES(13,'myValue')

-- Delete old record
DELETE FROM YourTable WHERE ID=3

-- Disable identity insertion
SET IDENTITY_INSERT YourTable OFF

Caution:

It's important to note that these alternatives should be used with caution, especially when foreign key dependencies exist. Careful consideration and thorough testing are necessary to avoid data integrity issues.

The above is the detailed content of How Can I Update an SQL Server Identity Column?. For more information, please follow other related articles on the PHP Chinese website!