DBCC CHECKIDENT Sets Identity to 0

You are right in what you write in the edit of your question.

After running DBCC CHECKIDENT('TableName', RESEED, 0):
– Newly created tables will start with identity 0
– Existing tables will continue with identity 1

The solution is in the script below, it’s sort of a poor-mans-truncate 🙂

-- Remove all records from the Table
DELETE FROM TableName

-- Use sys.identity_columns to see if there was a last known identity value
-- for the Table. If there was one, the Table is not new and needs a reset
IF EXISTS (SELECT * FROM sys.identity_columns WHERE OBJECT_NAME(OBJECT_ID) = 'TableName' AND last_value IS NOT NULL) 
    DBCC CHECKIDENT (TableName, RESEED, 0);