33. The system as recited in claim 32 , wherein the processor prompts the user to select preferences to be used during tuning based on whether the database query includes at least one of a NOT EXISTS, a NOT IN and an ALL clause.
33. The system as recited in claim 32 , wherein the processor prompts the user to select preferences to be used during tuning based on whether the database query includes at least one of a NOT EXISTS, a NOT IN and an ALL clause. 36. The system as recited in claim 33 , wherein the preferences include rewrite preferences for enabling a user to select whether to use at least one of a NOT EXISTS operator and an outer-join to convert subqueries joined by a NOT In operator.