Edbms In The Expansion Of Object-oriented Key Technologies And System Applications

This thesis discusses several research results on engineering database management system (EDBMS) and object-oriented key techniques, which mainly includes an O-O data model, data type expansion, encapsulation, inheritance, version management and the implementation of an expansive EDBMS/2 based on EDBMS/2.By expanding some key O-O techniques in EDBMS/2, a relation + object-oriented database management system prototype is designed and implemented, which has not only traditional RDBMS function but also basic O-O database function such as object, complex object, inheritance and encapsulation. If the O-O's features are removed , it is a traditional relational database management system.Data type R is presented, which represents a basic concept of O-O--the value of an object is an object too. Using data type R to establish the nested network relation among tuples/tables , the semantic link for IS-PART-OF is described and operated according to the rules. Data type R supports a new method for describing and processing the complex relations.Encapsulation and information hiding are enforced in our system, which supplies the logic data independence. Methods can be specified on tables, tuples and also some attributes of a special tuple, many methods are also permit to defined on a table. Users can program their method by themselves.All objects in database can be organized to form a network structure according to the inherit relation, the father can have several sons, son has several fathers (multi-inheritance). Apart from inheriting static data structures , the dynamic operations (methods) can be inherited too. Inheritance presents semantic link IS-A among objects. Users define inheritance and the system maintenances it automatically. Choosy multi-inheritance is proposed. Compared with the method of multi-...