Modeling and transformation of object-oriented conceptual models into XML schema

Abstract

EXtensible Markup Language (XML) is fast emerging as the dominant standard for describing data and interchanging data between various systems and databases on the Internet. It offers the Document Type Definition (DTD) as a formalism for defining the syntax and structure of XML documents. The XML Schema definition language as a replacement of DTD provides more rich facilities for defining and constraining the content of XML documents. However, to enable efficient business application development in large-scale e- Commerce environments, XML lacks sufficient power in modeling real-world data and their complex inter-relationships in semantics. Hence, it will inevitably be necessary to use other methods to describe data paradigms and develop a true conceptual data model, and then transform this model into an XML encoded format, which can be treated as a logical model. In this paper, we present the way to model XML and to transform the Object Oriented (OO) conceptual model into XML Schema. We choose the OO conceptual model because of its expressive power for developing a combined data model. The paper first discusses the modeling of XML and why we need the transformation. Then, several generic transforming rules from the OO conceptual model to XML schema, with the emphasis on the transformations of generalization and aggregation relationships, are presented. Different perspectives regarding these conceptual relationships (e.g., ordered and homogeneous composition in aggregation relationships, inheritance and overriding in generalization relationships) and their transformations are particularly discussed.