XPath Query Algorithms Of XML Stream

XML has become the standard of data description and exchange. It isused in many fields. As the evolution of XML technology, more and moreinformation has been described and exchanged in XML. Meanwhile, thestudy on XML stream querying is one of the hottest topics among thedatabasecircleallovertheworld.In existing XMLquery algorithms the whole document must be loadedinto memory. The method can't handle with big XML document and XMLstream. A different method for query processing is presented in the paper.According to the query expression, a query automaton is build. The XMLstreamisparsedintoelementtags andevents stream.Theeventtriggersstatestransition of query automaton. The stream fragment will be put outimmediatelywhile itisfitforthequery.A prototype model that is used for XML stream query is introduced.The model could evaluate the XPath expression and get the resultimmediately. At last, we make a comparative experiment to investigate thememory use between memory-based algorithm and the stream-basedalgorithm.The system can be used in some data-intensive applications. In these applications, traditional model can't deal with the streaming data. Theresearch in this paper contributes to the theory and practice of this kind ofapplications.