Study On Aspect-Oriented XML Data Management Techniques

With the development of Internet and computer technology,XML has been becoming a de facto standard for information representation and data exchange over the Web due to its self-description and flexible data structure properties.With the strong modeling ability of object-oriented methods,it is possible to improve the modeling ability of XML data models by extending XML with some object-oriented features.Traditional object-oriented techniques cannot fundamentally resolve the code tangling and scattering problems caused by the high system complexity.Aspect-oriented programming(AOP) methodology is introduced to solve these problems.After systemically analyzing and studying AOP techniques,an aspect-oriented framework is proposed in this dissertation to manage XML data.The main contributions of this dissertation are summarized as follows.(1) After analyzing aspect-oriented models and discussing some problems in practice that could not be solved by object-oriented theory,we extend XML document models with aspect-oriented techniques.The extended XML model has more object-oriented features and aspect-oriented features,including multiple inheritance,blocking,overriding,pointcut and weaving.(2) We propose a new method of XML data storing and querying.It adopts SAX technology to output XML streams,extends each element with Prefix code with the analyzing of Prefix code, and stores them into the relational database with others information.The new method can efficiently store and query data-centric documents with large graularity.(3) We present an effective method to compress the original extended Prefix code.The method recodes the redundant information to solve the problem that the original extended Prefix code has larger space complexity space when storing the large XML documents. (4) We improve the structural join algorithm of ancestor/decendant and parent/child over the single XML document,and propose a merge-based structural query algorithm over multiple documents to adapt to the query of the aspect-oriented definition of the XML Schema in the case of multiple documents.The proposed algorithm can further reduce the cost of scanning documents by utilizing the features of XML data,indexing and information waving into the documents.Finally,a lot of experiments are conducted to show the effectiveness and efficiency of the proposed algorithms in this dissertation.