Web Data Integration for E-Commerce Applications

useable, e-commerce applications require systematic development, including data integration. Traditionally, the integration proceeds in a bottom-up way. This article discusses the problems and proposes a top-down approach to overcome some of the problems. A combined yo-yo approach aims to exploit both strategies' benefits. E-commerce is an application domain in which integrating Web data from different information systems is a central problem. 1 For e-commerce applications , often interorganizational processes must be supported, whereby the individual information systems are highly autonomous, making the integration process an even more challenging task. For a scalable integration of autonomous, heterogeneous information systems' data, engineers need a systematic process. Traditionally, heterogeneous information system integrations proceed in a bottom-up way—we analyze the information models of existing (legacy) systems and subsequently integrate them. One result of the traditional bottom-up approach is that the overlaps among the component system's models—not the global applications' require-ments—determine the (merged) integrated data models' structure. The maintenance of such integrated models is a problem, because the merged models rapidly become very complex; usually more complex than required for the actual integration goals. This situation can lead to severe scalability problems with respect to execution performance , usability, and maintenance. Another way to approach heterogeneous information systems' integration is a top-down process. Starting with common models based on the requirements of new (global) applications and on domain-specific standards, we can integrate the individual component models into these common models. Still yet, another approach—called the yo-yo approach—combines bottom-up and top-down strategies in a way that exploits their benefits and serves as a migration path from the traditional bottom-up approach toward an ideal top-down approach. Traditional bottom-up integration One characteristic result of the bottom-up construction is that the component models' overlap-pings greatly determine the integrated model structure. For instance, many object-oriented integration approaches resolve semantic overlappings by introducing generalized classes so that the original inheritance hierarchies are subhierarchies of the resulting merged hierarchy (upward-inheritance principle 2). These approaches take over the inheritance hierarchies from the component models to the integrated model and adapt them to each other. Consequently, the resulting merged hierarchies may become needlessly complex. I illustrate these problems by examining two sample national banks using bottom-up database integration. These imagined banks aim at a joint venture to create an international virtual bank that offers banking services on the Internet marketplace based on their local services and systems. The first local component system stores account …