Study On Techniques Of Object-Oriented XML Data Management

With XML becoming standard for information representation and data exchange over the Web, the need to exchange and process XML data over the Web is dramatically increasing. Therefore, it is important to solve the problems to store, index and query XML documents. On the other hand, due to the strong modeling ability of object-oriented methods, how to extend XML with some object-oriented features and manage these object-oriented XML data for improving the modeling ability of XML data model are critical research issues. Major contributions of this dissertation are as follows.(1) We extend DTD, called object-oriented DTD, with element hierarchy, multiple inheritance, overriding, blocking, polymorphism, and conflict resolutions. Moreover, we present validation rules to validate if an XML instance document conforms to an object-oriented DTD.(2) First, we extend the XML-RL data model as Complex Object Data Model with element hierarchy, multiple inheritance, overriding, blocking, polymorphism, and conflict resolutions. Then, we extend ruled-based XML-RL Language with polymorphic element and reference as well as exclusive element and reference. Moreover, the syntax and semantics of the extended model and language are described systematically.(3) Distributed and Centralized storage methods have been devised and implemented to effeiciently store object-oriented XML documents. As for distributed storage methods, an attribute or element inherited from superclass resides in object of superclass, an attribute or element defined oneself resides in its own object. As for centralized storage methods, all attributes and elements reside in their own object, there is not any subclass instance but direct instance in superclass object.