Representing generalization/specialization in XML schema

Abstract

XML is an effective universal data-interchange format, and XML Schema has become the preeminent mechanism for describing valid XML document structures. Generalization/specialization and its constraints are fundamental concepts in system modeling and design, but are difficult to express and enforce with XML Schema. This mismatch leads to unnecessary complexity and uncertainty in XML-based models. In this paper we describe how to translate various aspects of generalization/specialization from a conceptual model into XML Schema. We also explore what needs to be added to XML Schema to handle the other aspects of this fundamental modeling construct. If XML Schema were to include our proposed constructs, it would be fully capable of faithfully representing generalization/specialization, thus reducing the complexity of the XML models that rely on generalization/specialization.