Key Technologies In XML Data Query Process

XML, which stands for Extensible Markup Language, with the advantages of simplicity,scalability,interoperability, and strong opening characteristics, is fast becoming a kind of standards for data exchange which is unrelated to the technology and transmission format. In view of XML have broad application prospects in many fields, and many studies about XML query there are forefront and hot topics. For example, in the field of database, in a sense XML as a database can be naturally usto represent nested data, and it have a more stronger ability. but there are many deficiency in XML data query field, the efficiency and speed need to be improved largely.XML data management system mainly solve the XML data storage management, query processing, access control, data updates. XML data storage management technology include data storage,data encoding, indexing and other methods. XML query processing and optimization, including XML query algebra, query processing, and query optimization. XML data query is a very important component of XML data management and it is a hot topic of the current academe. According to the different query patterns XML Query can be divided into two main parts:XML Query query mode and XML IR queries. XML IR can also be devided into three parts:XML IR/keyword method, XML IR/query methods and XML IR/fragment method.This paper studies some of the key technologies of XML queries, consisting mainly three parts:first, introducing briefly the basic concepts of XML data query, and designing a optimization mehod for Xpath expressions. Secondly, we analyzed the concept and representation of the current popular XML query algebra-OrientXA, then we proposed a new query optimization approach based on this query algebra; Finally, because XML query process often involves several similar XML fragments, and we sometimes want to find out same information in different XML Data, thus, this paper presents a tree model of XML Data with labels, based on this model, we design a matching algorithm, some experiments show that the algorithm has high feasibility.