When the dataset represents a query that does not return a result set, you can't use the RecordCount property to ascertain the number of records affected by the query. In such cases, read RowsAffected to determine how many rows were updated or deleted by the query when it executed. If no rows were updated or deleted, RowsAffected is zero. RowsAffected is -1 if the query could not be executed due to an error condition. (This latter situation typically follows the throwing of an exception.)