Research On Data Query Optimization Based On XML Database

XML is released as a markup language by W3C in 1998. As a result of its unique technique advantage, XML rapidly becomes the standard of data representation and exchange on the Web.Therefore,for building up various applications based on XML, it is initially important to accurately and effectively query/capture data from XML data source.On the basis of the automata technique, this paper discusses the technique of XML document query optimization by theory.This paper first has conducted the research to the automaton technology in the XPath inquiry's application. With the focus on XML inquiry optimization techniques based on automaton, it introduce the main idea of the automaton technology uses in the XML document inquiry, it analyzes and compares to several kinds based on the automaton technology's inquiry optimization method,it proposed XPath inquiry model based on the tree automaton technology's, which proposes the improvement algorithm to the original model. it introduce construction method of single and many XPath expression model, it simultaneously introduce movement example based on the tree automaton's inquiry model in XML documents. Finally it introduce the corresponding structure algorithm and the movement algorithm.Then, With the focus on the deficiency which exists the present XML documents inquiry optimization techniques research,this paper propose one kind of highly effective inquiry optimization method based on the view. this method include two key technologies: First, chain tree index structure; Second, inquiry optimization techniques based on view.It union these two technologies, it simultaneously also applies the automaton technology to the choice of effective view,it comes to search the effective view effectively and fast using the index structure and the automaton technology from the massive view which assigns. It improve the inquiry speed greatly, it realizes the XML documents inquiry optimization perfectly.At last,we design and realize an XML document processing system.According to the essential idea of XML query optimization technique presented above,we analyze and design the architecture of the system.The system first processes effective view's validation to the XPath query that user submits,then implements the optimization proeessing with the query optimization in this paper,finally carries it out and gets results.Moreover,the paper also presents two scenarios to test the system.It's verified from the experiment results that the new query optimization method presented in this paper can highly improve the XML query efficiency.