An Examination of Multi-Tier Designs for Legacy Data Access

<p>This work examines the application of Java and the Common Object Request Broker Architecture (CORBA) to support access to remote databases via the Internet. The research applies these software technologies to assist an Air Force distance learning provider in improving the capabilities of its World Wide Web-based correspondence system. An analysis of the distance learning provider's operation revealed a strong dependency on a non-collocated legacy relational database. This dependency limits the distance learning provider's future web-based capabilities. A recommendation to improve operation by data replication is proposed and the implementation details are provided for two alternative test systems that support data replication between heterogeneous relational database management systems. The first test system incorporates a two-tier architecture design using Java and the second system employs a three-tier architecture design using Java and CORBA. Data on replication times for the two-tier and three-tier designs are presented revealing a greater performance consistency from the three-tier design over the two-tier design for varying client platforms and communications channels. Discussion of a small-scale proof-of-concept system based on the three-tier design is provided along with a presentation of the potential for the technologies applied in this system to benefit Air Force web-based distance learning.</p><p>This work has been selected by scholars as being culturally important and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact and remains as true to the original work as possible. Therefore you will see the original copyright references library stamps (as most of these works have been housed in our most important libraries around the world) and other notations in the work.</p><p>This work is in the public domain in the United States of America and possibly other nations. Within the United States you may freely copy and distribute this work as no entity (individual or corporate) has a copyright on the body of the work.</p><p>As a reproduction of a historical artifact this work may contain missing or blurred pages poor pictures errant marks etc. Scholars believe and we concur that this work is important enough to be preserved reproduced and made generally available to the public. We appreciate your support of the preservation process and thank you for being an important part of keeping this knowledge alive and relevant.</p>