Formal Framework of XML Document Schema Design

Designing “good” XML documents is a very difficult task for a database designer. Although many theories for XML database design have proposed, none of commercial design tool for XML document design has been developed to assist the XML document designer. In this paper, the authors present a formal framework of XML document design by incorporating a conceptual model of XML schema called Graph-Document Type Definition (G-DTD) with a theory of database normalization. This framework is designed as a blueprint to help the XML database designers to perform the XML document schema design quickly and accurately. The G-DTD is used to describe the structure of XML documents at the schema level. A set of normal forms for G-DTD on the basis of rules proposed by Arenas and Libkin and Lv. et al is used to provide a guideline to a well-designed schema for XML documents. They develop a prototype of XML document schema design using a Z formal specification language. Finally, using a case study, this formal specification is validated to check for correctness and consistency of the specification. Thus, this gives a confidence that the authors’ prototype can be implemented successfully to generate an automatic XML document design.