The Research Of Inheritance Theory And Realization Of Complex Object In ORDBMS

Recently, the application of Database is expanding, it has reached many new areas such as multimedia, communication , CAD/CAM and CIM. These applications have propounded new requirments for database, for example, complex data types, long transaction and nesting transacting. Yet the traditional database can' t meet those requirements. Although OODBMS can adpat to these requirements of non-traditional application, it lacks unified data model and pure OODBMS can' t support SQLDB query. So OODBMS may not be very popular. With the development of the Object-Oriented technology,ORDBMS which based on the Relational Model, has been one of the most ubiquitous and promising research and application fields in recent years. It absorts the merit of OODBMS and RDBMS, it inherits the mature technology of RDBMS. On the other hand, it imports the technology of 00, so it can boost up the ability of handle complex object, etc. So, we can say ORDBMS is a new generation of database system, it is the next tidal wave of the database system developing.First, this paper introduce the development of ORDBMS, it summarize the concept of ORDBMS from all angles. Then, we compare the different among RDBMS, OODBMS, ORDBMS. After analyzing the concepts of ORDBMS , we put emphasis on the study how to store and manipulate these complex objects which include user' s types and how to realize them on the prototype of ORDBMS designed by us. Then we provide a system of axiom based on class level, some algorithms about how to transform class level to database model, three aproches of how to realize properly inheritance in class level. After having a set of correct and effective axiom, realizing properly complex object and inheritance is the key to ORDBMS. Only solving these problems .ORDBMS can inherit the merit of both the relational system and Oriented-Object System, and have an abroad research future and actual application future.