Supporting iterations in exploratory database reengineering processes

Key technologies like the World Wide Web, object-orientation, and distributed computing enable new applications, e.g., in the area of electronic commerce, management of information systems, and decision support systems. Today, many companies face the problem that they have to reengineer pre-existing information systems to take advantage of these technologies. Various computer-aided reengineering tools have been developed to reduce the complexity of the reengineering task. A major limitation of current approaches, however, is that they impose a strictly phase-oriented, waterfall-type reengineering process, with little support for iterations. Still, such iterations often occur in real-world examples, e.g., when additional knowledge about the legacy system becomes available or when the legacy system is modified during an ongoing migration process. In this paper, we present an approach to incremental consistency management that allows to overcome this limitation in the domain of database systems by integrating reverse and forward engineering activities in an intertwined process. The described mechanism is based on a formalization of conceptual schema translation and redesign transformations by graph rewriting rules and has been implemented and evaluated with the Varlet database reengineering environment.