1. A database processing procedure generating method in a database processing system for supporting a plurality of storage structures, said database processing procedure generating method comprising: a first process step for accessing structure definition information for information relating to a combination of a plurality of different basic data organizations associated with a query from a dictionary for storing storage structure definition information relating to the combination of basic data organizations of each type of said plurality of storage structures; a second process step for generating an accessing procedure forming a part of a database processing procedure to be prepared with access parts, each of said access parts corresponding to an access method to each of said basic data organizations, for each of a plurality of storage structure definitions associated with a query; a third process step for generating a database processing procedure in response to a whole query based on a certain combination of said access procedures generated in said second process step; and a fourth process step for evaluating and selecting a procedure using cost evaluating parts corresponding to access parts forming a database processing procedure.