DATA BASE MANAGEMENT SYSTEM BASED ON EVENT RELATION DIAGRAM

摘要

PURPOSE: To provide a data base management system for flexibly corresponding to the change of conceptual schema and a using data base system without necessitating newly redesigning an internal schema and an external schema at the time of the change of the conceptual schema and the using data base system. ;CONSTITUTION: The conceptual schema designed in an ER diagram are utilized in the form of the ER diagram as the internal schema and the external schema and are managed respectively at an internal schema management part 1 and an external schema management part 2. Thus, since the redesign of the internal and external schemas due to the change of the conceptual schemas is unnecessitated and also only the sub set of the ER diagram is cut out for designing the external schema, the design and addition of the external schema are facilitated and labor for designing a data base can be saved.;COPYRIGHT: (C)1994,JPO&Japio