1. A method for organizing multiple execution plans for database query, the method comprising the steps of: arranging a plurality of execution plans into a plurality of groups, each group having at least one operator associated with at least one operator in another of the groups; determining identification data for each operator related to other operators in the other of the groups; and determining identification data for each execution plan based on the identification data for each operator, whereby the identification data for each execution plan uniquely identifies the respective execution plan from all other execution plans.