8. The method as recited in claim 7 , further comprising prompting a 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.
8. The method as recited in claim 7 , further comprising prompting a 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. 12. The method as recited in claim 8 , wherein the preferences include rewrite preferences for enabling a user to select at least one of a conversion of NOT EXISTS operators to a NOT IN operator and conversion of the selected database query to an outer join.