179 research outputs found

    Integration of Object Oriented Host Program with Network DBMS

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    AbstractSeveral 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

    A temporal and spatial locality theory for characterizing very large data bases

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    Bibliography: p. 22-23.Stuart E. Madnick, Allen Moulton

    A machine independent implementation of a data storage description language.

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    This thesis presents the methods, results and conclusions of a design and implementation of a Data Storage Description Language (DSDL). The DSDL chosen was the CODASYL Network DSDL. The design supports storage independent manipulation, for access and reorganisation of partitioned schema records, sets and indexes. The production of a Table Generator to compile the DSDL provided the basic structure and mechanisms of a run-time system for the support of dynamic incremental reorganisation. The project developed storage constructs and techniques for a machine independent Data Storage Description Language and evaluated these ideas through an implementation.The particular objectives of the project included the evaluation of the efficiency of the techniques regarding the criteria of the storage space of tables and records, time for processing, and ease of reorganisation. By developing a run-time system to control dynamic reorganisation of a database given a new version of the storage schema for the same database

    Coupling engineering workstations to a database server

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    A DBMS kernel architecture is proposed for improved DB support of engineering applications running on a cluster 01 workstations. Using such an approach, part of the DBMS code - an application-specific layer - is allocated close to the corresponding application on a workstation while the kernel code is executed on a central server. Empirical performance results from DB-based engineering applications are reported to justify the chosen DBMS architecture. The paper focuses on design issues of the application layer including server coupling, processing model and application interface. Moreover, a transaction model for long-term database work in a coupled workstation-server environment is investigated in detail
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