Practical Case Study of a Web-based Tutor Payment System

The emerging use of object-relational databases with Web technologies has only recently begun. This chapter discusses a practical realization of an application using this technology. The aim is to show readers how to construct a full application from a design using object-oriented features up to the implementation. In this chapter, we highlight important or difficult stages with an emphasis on the mapping of object design into Oracle 8i and the use of stored procedures with the extended features for objects manipulation of Oracle 8i. This enables developers to construct professional Web applications achieving a high modularity and evolution capacity with an accelerated development phase in comparison with the traditional approach. INTRODUCTION This chapter is dedicated to the study of a practical case. We will show a way of implementing a Web-based application using an object-relational database. To 701 E. Chocolate Avenue, Hershey PA 17033-1240, USA Tel: 717/533-8845; Fax 717/533-8661; URL-http://www.idea-group.com ITB8243 IDEA GROUP PUBLISHING This chapter appears in the book, Web-Powered Databases, edited by David Taniar. Copyright © 2003, Idea Group Inc. Practical Case Study of a Web-Based Tutor Payment System 89 Copyright Idea Grou p Inc. Copy right Idea Grou p Inc. Copy right Idea Grou p Inc. Copy right Idea Grou p Inc. justify the use of an object-relational database rather than an object-oriented database or a relational database, it is important to take into account the constant need of companies to produce faster applications. The object-oriented model with its characteristics of modularity, reusability, and extendibility, and its ability to stay the nearest as possible from the real world, is very suitable for these requirements. However, object-oriented databases are still not widely deployed and most companies want to be able to use the object technology without having to change their database systems. Moreover, because developers know relational systems very well, applications may be developed faster. This is the reason that we chose a system combining the advantages of relational and object-oriented features. We chose Oracle 8i. Since version 8, Oracle has provided some object functionalities, such as objects, ref types, collection types, nested objects, etc. This new era of DBMS (Database Management Systems), where relational DBMS is enhanced with some object-oriented features, is often known as Object-Relational DBMS (Stonebraker & Moore, 1996). Consequently, database design using object-oriented modeling needs to be transformed into an object-relational database schema for implementation (Rahayu and Chang, 1993). In this case study, the Web part of the application is implemented using PHP (McCarty, 2001). This allows us to demonstrate the use of a scripting language to access a database and present the information to users. PHP has also been chosen as much for its ease of use as for its ability to demonstrate how to use a language combining presentation and logic facilities. The implementation of the database and the way to construct queries are also explained and demonstrated using PL/SQL (Urman, 1997). The rest of this chapter is organized as follows. Firstly, we describe the case study and the database design. This is then followed by the implementatio architecture. The database layer implementation using the transformation methodology is later described. The components of the two logic layers, the database and the application logic respectively, are then detailed, as well as the presentation layer. Finally, some discussions and conclusions are given. TUTOR PAYMENT SYSTEM: A CASE STUDY In this section, we briefly describe a tutor payment system, and the design aspect of the system, using an object-oriented modeling. Problem Descriptions The case study is an online tutor claim system, which allows casual tutors to submit claims of payment for their work. This payment claim is done fortnightly as the payment in the Australian University system is carried out every fortnight. The casual tutors are students, mostly postgraduates hired by a university department for each subject in each semester. They will help lecturers in their work, doing marking, labs, tutorials, and consultations. 31 more pages are available in the full version of this document, which may be purchased using the "Add to Cart" button on the publisher's webpage: www.igi-global.com/chapter/practical-case-study-webbased/31425