4. The computer-readable program code embedded in the memory of claim 3 , wherein the matching items in the select list is performed using a select list index.
4. The computer-readable program code embedded in the memory of claim 3 , wherein the matching items in the select list is performed using a select list index. 5. The computer-readable program code embedded in the memory of claim 4 , wherein a matched item is an item in the select list of the new query that is found in the select list index, and an unmatched item is an item in the select list of the new query that is not found in the select list index.