There are two ways to find the changes using the DataSet object:
GetChanges(): The DataSet object that has changed after it was loaded or since the  AcceptChanges() method was called is returned.
HasChanges(): If any changes have been made since the DataSet object was loaded or after a  method call to the AcceptChanges() was made, it will be indicated. Use the RejectChanges() method, if you want to reverse the entire changes from the time the  DataSet object was loaded.