Research On Xquery Query Over Xml Update Streams

With the widespread use of the Internet, some new data-intensive applications has been widely recognized, maded the stream data processing technology aroused widespread interest in the research community,such as Wed blog,financial analysis,network monitoring and security,sensor networks,telecommunications data management,manufacturing,location search,location Search,sock Information Inquiry etc. whose feature is that data is reaching quickly in the form of a continuous data stream in uncontrollable order on line and can not be stored, but queries are stored lastingly. This type of data stream application has produced some new problems. So the theory and technology about the XML data stream management and query have become the hot research in the field of data stream currently.XML data stream processing system is running on the Internet. The users are massive in this environment. They use XQuery expression to describe their queries needs. The core of the XQuery statement is XPath, XML stream query problems mainly attributed to the XPath query, how to extract the XPath form the XQuery,how to use XPath expressions efficient query XML Stream is the key issues for theXML stream processing.Introduced the concept of XML update stream into the XPath query field,to resolved the issue of receive continuous precise query answer. This is the emphasis of this paper.In this paper, aimed at receive continuous precise query answer over the XML stream XQuery qrocessing,combination the attributins of XML update stream and XQuery processing technology, proposed a solution based on the XML update stream. Dynamically insert the update event into the XML stream, to form XML update stream, so that we can receive continuous precise answers. XQuery based on XPath queries use FLWOR expressions to achieve complex queries on XML data stream.Extract main path from the expressions, Separate the absolute path and relative path, merge the path which have dependency relationship, rewrite FLWOR expressions, Improve the efficiency of XQuery queries. Experimental results show that, our method can improve the efficiency of XQuery queries, get the precise results.