Research On Approximate Tiwg Pattern Matching Of XML Based On DTD

Internet has completely permeated into all aspects of people's lives. XML(Semi-structured language)has become one of the most important data carrier, and has become the standard of describing data in Web services, e-commerce, digital libraries, and many other network-related applications. In recent years, how to effectively manage and query the XML data and how to facilitate the user extracting the information they need from the flood of XML have got more and more domestic and foreign scholar's attention. Therefore, many XML data query algorithms came into being, making XML data query become a hot spot of XML data management.In order to utmost satisfied the users'convenience, the paper analysis the lack of the existing query technology and twig query thoroughly. By studying this paper proposed a new twig join algorithm, It does not only meets the strict matching, but also satisfies the query needs with clear query target when the user doesn't understand the pattern information of the DTD, realized flexible matching.The main work and innovations are as follows:1. Describes node coding schemes of the XML document, and introduces the current research and the shortcomings of twig query. Based on the characteristics of query algorithm, we choose to use the prefix code and the extend prefix encoding.2. In this paper, we propose XML-twig target path approximate matching twig join algorithm based on DTD named FTJ using the prefix code to encode on the DTD node, and check whether the query path match or approximate match the DTD, thus, get an approximate matching query twig Q, then call TJFAST. By comparison, the Experimental result shows that the algorithm the paper proposed can satisfy the maximum requirements of the user. The algorithm includes two phrases:the target node preprocessing and twig query pattern matching. At last, gave performance verification by experiment.3. Based on the first two studies, chapter 4 proposed and designed XML-twig target path approximate matching twig join advanced algorithm based on DTD, this advanced twig join algorithm can support twig query more flexible.The paper researched on how to querying XML database effective and flexible, studying a better solution. This paper proposed a more flexible search algorithm to meet the user's flexible query strategy based on twig join algorithm which is hot in XML query research. All makes this exploratory research has both theoretical research value, but also has great application value and practical significance.