Research Of Query Method For A Large-scale XML Information

The rapid development in web technology makes more and more information transferred and shared, so XML technology is appeared to solve it. XML has been a standard to denote and tool to exchange data in Internet, it opens up a new field in database application, However, XML data is semi-structure and its path querying is different from relation database querying, These make function that relation database system manages XML data limited at a large degree.That One obvious character of XML data is data redundancy must be faced whichever model is used to store data. Because data redundancy not only makes store space wasted but also adds I/O processing to query, efficiency is reduced.At present, compression is an effective method to contract XML document, but XML document compressed must be decompressed to validate, query and other operations, that make time and space costly in some applications, such as handhold equipments and server to receive XML document. How to effectively compressed XML document and query documents compressed are problem to solve in data exchange based on XML.The paper eliminates data redundancy from text and structure of XML based on semi-structure of XML. BWT is adopted to eliminate redundancy and shows by experiment that the efficient in querying text compressed is high. After analyzing defect in present structural link for XML text redundancy, it proposes and proves that there are iterative structural link paths in link expressions based on relations in parents-children and ancestor-posterity. It proposes a method called ESL by which structural indexes are much less than initial datum.Finally, the paper proposes a model to process querying in XML where compressing module adopts last technology and makes a primary research to complete it.