1. A method for preventing Halloween problem conflicts when updating records in a database system, comprising the steps of: receiving an update query from a user of said database system wherein said update query defines a desired result of an update of said records in said database system; determining, responsive to receipt of said update query, whether Halloween protection is necessary in an update plan for executing said update query; generating, responsive to said determining step, said update plan where said update plan is a group operators with at least one operator of said group of operators being an update operator and where Halloween protection is provided for at least one column of at least one record source by at least one Halloween protection operator which produces output for which said update operator is not a direct consumer; and processing said records with said update plan to provide output records satisfying said update query wherein said records are free from Halloween problem conflicts.