An integrated database system for performing data processing utilizing plural types of databases. A Meta level system 15 includes a script interpreter 8 which interprets an inquiry represented by a script form which has been addressed to a database to issue a primitive corresponding to the inquiry and combines replies represented by a primitive form received from plural types of databases 11. A local database system 14 includes a primitive processor 9 which transforms the primitive into a control command corresponding to the type of the database 11, outputs the transformed command to the plural types of databases 11, and replies to the Meta level system 15 with the process result represented by the primitive form.