Research And Implementation Of Querying Mechanisms Of XML Documents Based On Chord Protocol

An important problem that confronts Peer- to- Peer Network is the efficient location of the node that stores a desired data item.The research focuses on the DHT (Distributed Hash Table) , because DHT lookup algorithms offer a scalable and efficient routing and object location platform for Peer - to - Peer networks. At the same time XML database technology is also rapidly becoming the Internet for data on express and data exchange standards. XML documents and fragments appear substantial, XML documents and query the effective management of same have also been widespread concern.To this end this paper of the protocol based on XML documents Chord query mechanism for research. Introduce one of the main representatives of the Chord algorithm, based on this model the XML document query mechanism, and its analysis of the specific implementation and system.We take up with the problem of querying XML data over a P2P network. In P2P networks, the allowed kinds of queries are usually exact-match queries over file names. We discuss the extensions needed to deal with XML data and XPath queries. A single peer can hold a whole document or a partial/complete fragment of the latter. Each XML fragment/document is identified by a distinct path expression, which is encoded in a distributed hash table. Our framework differs from content-based routing mechanisms, biased towards finding the most relevant peers holding the data. We perform fragments placement and enable fragments lookup by solely exploiting few path expressions stored on each peer.Realize the whole system is based on Chord routing protocol for the P2P network structure, designed mainly divided into three components, namely memory modules are XML, query processing module and the network structure module. Taken up at tiered implementation strategy, divided into user interface layer, application interface layer, service layer, Chord layer, network layer. As XML documents using JDOM parser implementation using Java language.Finally this article to the method which proposed has carried on the corresponding experiment analysis and the appraisal.