Abstract: The present invention relates to an optimization method in a database management system having the function of accessing external databases. Conventionally, whether functions contained in a query can be executed in external databases depends on a database management system having the functions, and therefore there has been a problem in that a database utilization method cannot apply to query optimization and query execution performance is reduced. To solve the above problem, a database management system having the function of accessing external databases is provided with an optimization step comprising the steps of: obtaining specification about whether to execute functions in a query in external databases; determining whether data referred to in a query is confined to one database; and determining whether a user specifies that the functions in the query are executed in external databases.

Abstract: The efficiency of development of an application program constructed of a plurality of application windows utilizing GUI controls is improved. By causing a GUI control property defining information selector to select GUI control property defining information defined by a GUI control property defining information definer, the selected GUI control property defining information is reflected upon the property of a GUI control used in an application window editor. When the GUI control property defining information is changed by the GUI control property defining information definer, GUI control information in synchronism with the changed GUI control property defining information is searched from GUI control information used in the application window editor and GUI control property defining information after changing is reflected upon the searched GUI control property information.