truncate command. This will delete data from table and also reset the identity column value to 0.truncate table [table_name] -- for example truncate table product
But the truncate command fails to delete the data if there is a relationship given to the table and the identity column is not reset.
The other way is...
In this case, first you need to delete data from the child and the master table.
After deleting data, fire this command and it will reset your identity column to 0.
DBCC CHECKIDENT('[table_name]', RESEED, [new_reseed_value]) DBCC CHECKIDENT('product', RESEED, 0)
DBCC CHECKIDENT can reseed (reset) the identity value of the table. For example, YourTable has 25 rows with 25 as last identity. If we want next record to have identity as 35 we need to run following T SQL script in Query Analyzer.
DBCC CHECKIDENT (yourtable, reseed, 34)