带Order子句的XQuery在XML流上的查询实现

XQuery Processing on XML Stream with Order Clause

随着XML的广泛应用,使得作为XML文档查询语言的XQuery成为人们研究的热点问题.将复杂XQuery在XML数据流上的查询应用于服务器/客户端模式来满足高效、实时查询的要求,所实现的XQuery查询原型系统XSIEQ支持嵌套、order子句的多关键字排序等.一次典型的XQuery查询过程可分为XPath查询、查询后处理两个阶段,本文着重描述查询后处理过程,最后给出了XSIEQ和Qizx在查询后处理时间性能上的对比及分析.

As XML has been widely used, XQuery, as a favorite language on XML query, has received considerable attention recently. In some applications especially data selecting and distributing, the results are required to be output immediately while parsing XML stream. In this paper, a server/client architecture is applied to resolving.the problem of efficient and immediate evaluation of XQuery over streaming XML data. The original XSIEQ（XML Stream Query with Immediate Evaluation） system is extended and tested in order to support complicated XQuery queries including nested queries and order clauses with multiple keys. A typic process of XQuery query is divided into two stages： XPath query and query post-processing. Algorithms on query post-processing are focus of this paper, and the query performance comparison between XSIEQ and Qizx is given in the end.