An Algorithm Of XML Tree Patern Extraction For XQuery

In the modern society, Internet is already a indivisible part of our daily lives, wheras effective data exchange is the foundation of the Internet.In response to the increasing heterogeneous nature of data in the Internet, the International World Wide Web Consortium(W3C) standardized XML(eXtensible Markup Language). XML is a cross-platform data exchange language which is also highly priced for its self-descriptive and tree-shape featue. Howerver the previous characteristics brings challenges for the XML query engine implementation.XQuery is the recommended XML query language of W3 C. In order to implement XQuery query efficiently, researcherintroduces the concept of tree pattern query for XML data. Tree pattern generation process employ the relevance of structural connections, extracts and combines them into a tree shape pattern; finally by combining with operators they turn into a query plan which is equivalent to the original. As the access to import data sources with the semantic of filtering,tree pattern matching reduces the size of immediate data effectively. Further, because of the need to maintain the query results in the case of completely change the query internal evaluation order, the tree pattern extraction method involves many details.Confronted with complicated data reorganization needs, the traditional methods usually ensure that by multiple tree patterns.This paper discusses a set of tree pattern extraction algorithm which is complete for XQuery. The detailed strategy fully analyzes the variables, multiple data sources, and iterative statements etc. The basic idea of the algorithms is extending structural connections greatly witout backtracking in the extracting process.Algorithm described here refers various features of XQuery syntax and the algorithms relatively independently. Thereforeit has practical value.Based on the algorithm discussed in the paper, the end of this paper displays the implementation framework and performance testing. System implementation and experimental results show the effectiveness of the algorithm discussed in this paper.