E-Hermes: An Xml Tool for the Classroom

Journal of Information Systems Education, Fall 2005 by Nicolaou, Andreas I, Essex, Patricia A, Raghunathan, Madhavarao, Liu, Li

ABSTRACT

This paper describes the development of an XML-based tool, called e-Hermes, suitable for use in a variety of instructional contexts. e-Hermes simulates the capabilities of a web-based system to handle customer order transactions and to apply both document structure (data format) validations and application (data content) validations. Students in Information Systems (IS) courses can use e-Hermes to support their learning about web-based database and system design principles, to practice using XML or to understand e-commerce transactions. Assignments are provided in this paper, along with an appendix for instructors who need more background in XML. This paper, therefore, presents important educational contributions in the field of information systems.

Keywords: Classroom Instruction, XML, Electronic Commerce Simulation

1. INTRODUCTION

The advent of modern technology has improved the ability of businesses to transact efficiently in electronic markets. Interorganizational exchanges in electronic markets may involve transactions between a business and one or more other businesses (business to business e-commerce) with or without the use of an intermediary. The extensible Markup Language (XML) is a generic markup language that, by defining document content, can enable systems in remote locations to exchange and interpret business documents over the Internet (Kim 2001; Murray 2002). This ability to generate, send, retrieve, interpret, transform, and process the data in electronic messages automatically is critical to the conduct of web-based electronic commerce (EC) without human intervention. Information systems students need

to learn about the implementation details underlying webbased business activity so that they understand the importance of data validation to the internal control climate of their employer or clients. Students benefit from a study of XML, also, in order to understand how it affects the conduct of web-based business activity. Additionally, they need to understand the underlying complexity of web-based databases that support concurrent online transactions. Past studies have explored the usefulness of XML as a medium of data exchange (Kirn 2001; Murray 2002) and have developed instructional resources for learning XML syntax (Lunsford and Bizarro 2003), but have not examined the issues investigated in this paper.

This paper describes the development of an XML-based EC system, called e-Hermes, suitable for use in the undergraduate information systems class. e-Hermes simulates the capabilities of a web-based system to handle customer order transactions and to apply both document structure (data format) validations and application (data content) validations. The use of this system allows students to visualize and experience online ordering more thoughtfully than they might from personal ordering experiences and still relatively realistically. Suggested assignments are presented along with an appendix to provide instructors with basic XML concepts. The paper concludes with recommendations for further using e-Hermes in experimental laboratory environments examining issues of continuous system assurance and online event data processing.

2. A MODEL FOR WEB-BASED EC

E-commerce transactions involve a number of separate processes, such as the transmission of data, the translation of exchanged documents using a shared schema, data processing, and updating of a database. Validation processes are critical to the successful implementation of web-based e-commerce and should be applied at all levels. Using XML, for example, a shared data schema can be defined for transacting parties and used to validate the structural format of documents submitted for processing. E-commerce systems also might apply real-time validation in order to ensure that data content included in transmitted documents meets business rules as defined in the firm's relational data model.

Figure 1 presents a general process for web-based EC exchange using XML techniques. Readers unfamiliar with XML might benefit from reading the Appendix A-XML Basics in order to aid with the following discussion. In this general model, the originator of a transaction will use a schema from the global repository or a customized file to generate an XML instance file for that transaction. After this partner sends its document in XML format over the network, the receiving partner validates the XML instance file against the same XML schema from the global repository or against the customized schema file. These procedures of parsing and validation ensure that the structure of the instance file actually conforms to the schema. The two parties need to agree on the XML schema in advance, and the schema is transmitted with the instance file or, alternatively, the schema's location is defined within the instance file. Validation of the instance file against the XML schema is processed on the server (the receipt) side.

After the file's format is accepted by the recipient, the file contents should be examined to determine the correctness of the data, as defined by the recipient's application rules and standards. For this purpose, the data content from the instance file can be extracted and translated into SQL statements. Then, the validity of the data is checked against the types of elements and relationships that are defined in the recipient's data model. Once validation is completed, the data can be processed to update the recipient's database.