Automated Reverse Engineering of Legacy 4GL Information System Applications Using the ITOC Workbench

Most contemporary fourth-generation languages (4GLs) are tightly coupled with the relational database and other subsystems provided by the vendor. As a result, organisations wishing to change database vendors are typically forced to rewrite their applications using the new vendor’s 4GL. The anticipated cost of this redevelopment can deter an organisation from changing vendors, hence denying it the benefits that would otherwise result, for example, the exploitation of more sophisticated database technology. If tools existed that could reduce the rewriting effort, the option of changing database vendors would become more economically feasible. The ITOC project is a large collaborative research initiative between the Centre for Software Maintenance at the University of Queensland and Oracle Corporation. The primary goal of the project is to develop tools to assist in the migration of 4GL information system applications. A tool resulting from the project has been utilised to recover design information from several deployed commercial applications. This paper describes the tool, evaluates its performance when applied to these applications and provides insight into the development of “industrial strength” re-engineering tools.