Xml Data Query Optimization And Processing Technology

With the rapid advancement of the web technology, the delivering and sharing of the information increases increasingly all over the world. The emergence of XML technique exactly deals with the above problem effectively. XML has become a standard for data expressing and a tool for information exchanging gradually, it will develop a new realm for the application of database. However, the semi-structure characteristic of XML data, the difference between the query of special XML path expression and the structured query language of relational database, make the relational database magnagement fucntion dealing with XML data limited.This paper focuses on the query language of XML data, the technologies of path expression optimizing and the query processing of XML data. This paper presents a new query language,X-SQL,for XML database, which supports the query of path expression for XML data.the opertation of XML data updating,the semantic describing of query result and is easy to use. Based on X-SQL query language, we present a path expression optimization algorithm, which reduces the length of path expression efficiently and improves the query efficency.then we present the query process algorithm based on query dependent tree, which makes use of the translation rules. translates the users'X-SQL query into corresponding execution sequence of structured query language and obtain the final query result. Making use of the above methods.we establish a XML database management system and evaluate the performance of the database.