DBCC CHECKIDENT ('[TestTable]', RESEED, 0)
This is useful for resetting the identity column if you ever make a mistake by inserting duplicated rows and end up deleting one of them. My use-case was that this identity column needs to be in-sync with the other databases and it is used as foreign keys in some other tables.
Alternatively, you can turn it off:
SET IDENTITY_INSERT sometableWithIdentity ON INSERT sometableWithIdentity (IdentityColumn, col2, col3, ...) VALUES (AnIdentityValue, col2value, col3value, ...) SET IDENTITY_INSERT sometableWithIdentity OFF