DBCC CHECKIDENT ('table_name', RESEED, new_reseed_value)

The current identity value is set to the new_reseed_value. If no rows have been inserted to the table since it was created, the first row inserted after executing DBCC CHECKIDENT will use new_reseed_value as the identity. Otherwise, the next row inserted will use new_reseed_value + 1. If the value of new_reseed_value is less than the maximum value in the identity column, error message 2627 will be generated on subsequent references to the table.

1. Consider our table having some row. Now we are deleting the table with query

DELETE FROM table_name

DBCC CHECKIDENT ('table_name', RESEED, 0)

The table will generate an identity value form 1 and not from 0.


2. Now we are truncating the table with TRUNCATE TABLE Statement.

TRUNCATE TABLE table_name

DBCC CHECKIDENT ('table_name', RESEED, 0)

The table will generate an identity value form 0.

During INSERT if there is an error, the row will not Inserted but the Identity value increased according to(IDENT_INCR) the Increment.