Resetting SQL identity columns

If you're somehow perfectionnist as I am, you probably want to reset the your identity columns when deleting all records from a table.

With SQL Server, you can do so by using the DBCC CHECKIDENT command.

DBCC CHECKIDENT ('MyTable', RESEED, 0)

Now if you want to reset the identity of a table that still contains some rows, you must reseed it to the last number used.

DBCC CHECKIDENT ('MyTable', RESEED, 123)