Integration of Object Oriented Host Program with Network DBMS

Several mapping techniques are in use for the storage of objects in Network Database Management System (NDBMS). Though there is a generation gap between the evolution of NDBMS and Object Oriented Technology (OOT), both are either analogous or complementary to each other. Therefore the mapping technique to map class diagram onto Bachman diagram has been evolved. Host program accessing the database and accessing the independent data file may differ in the number and use of attributes and classes. Hence along with the mapping techniques, the implementation subsets of structural and behavioral aspect are to be considered. Moreover, the persistent closure (connected dependent objects) is to be maintained during the storage and retrieval of the objects. Thus, the mere mapping technique is not sufficient for the storage and retrieval of objects as the host program has to establish the relevancy of the database with respect to its authorized subset. In this paper, we have made an attempt to develop a guidelines to assist the programmer to determine the closure of every mapped class and accordingly to design the persistent constructor and loader for the storage and retrieval of the objects respectively. The persistent closure is determined by the type of interrelationship (degree of cohesion) between objects (classes) is identified. For illustrative portion of the class diagram depicting the business process and its implementation in the NDBMS, a table containing the implemented classes with their connected classes is prepared, and then the guidelines are proposed to integrate object oriented host program to access the database through NDBMS.