In last years,with the Object-Oriented Programming popular and the field of database application extend-ed, many DBMS manufacturers integrate the object model into traditional Relational Database Management Systems(RDBMSs)one after another,in order to meet the needs for complex engineering applications. This paper firstly givesa total remark on the reason for the prevalence of the Object-Relational Database Systems (ORDBMs)and on the ben-efit of ORDBMSs comparing with RDBMSs and Object Oriented Database Management Systems (OODBMSs) ,then in-troduces an approach for ORDBMS architecture which integrates the Java class library into ORDBMS metadata repos-itory.
