To make efficiently information of many databases manageable by purposes using an object-oriented database.

Data to be managed are generated as an object such as a business trip object. An OODB server 10 manages the object in an object database 12. Real data are mapped in a relational database 13 by a purpose that corresponds to the object and are saved. In the object database 12, only the attribute of the object is saved as a class. For generating a new class, an abstract object for recording a relation with an attribute stored in an existing class is newly generated, and is collectively recorded. By referring to the abstract class, modification, deletion or the like provided to an object is reflected in existing objects in a concatenated manner.