how to use commit rollback in linq

before any changes occure on the database you have to have a db.submitchanges() before the changes are submitted. Anything that happens in the mean-time will be held in a transaction anyway. :

public void ChangeData(string newData)
{

            //Always use a new instance of the DataContext when making changes to the data as all changes made would be submitted otherwise
            DataContext1 db = new DataContext1();

            //throws an error if it find 0 or >1 record.  can be useful
            data recordToUpdate = db.datas.Where(d => d.data_id == id).Single();

            //change data in the record instance.  Remember that this record is tied to the db instance of the database.  No other instance contains this change
            recordToUpdate.email_address = newData;

            try
            {
                //you could leave out the try and catch the error higher up
                db.SubmitChanges();
            }
            catch
            {
                //notify? raise error?
            }
  //once db loses scope the changes vanish with it
}

Just remember that with link to sql, no actual changes happen until you try to submit the changes to that db instance