Study Of An XML Query Language XQuery And Its Extension

XML querying needs extracting datas from actual and virtual documents on the World Wide Web, and supplies the interaction between between the Web world and the database world. Ultimately, collections of XML files will be accessed like databases. XML query language XQuery is the extension of navigation language XPath, and it is a functional language which has simple syntax and strong expressive force. XQuery has the internal relationship with XML data structure, so we can write business logic expediently by it. It can manipulate XML data essentially too.The purpose of this paper is to go into the specifications of XQuery and extend the function of XQuery for querying XML document collection. On the basis of deep comprehension of XQuery specifications and sufficient research on the present status of XQuery technology, we discuss the feasibility of extending XQuery, and bring forward an extending thought. XQuery language interpreter is the hard core of this language's implementation. This paper discusses the used tools and several significant issues, and presents the system framework of XQuery language interpreter. In the end of this paper, we present a prototype to extend XQuery functions, and analyse its application support.