Analysis And Application Of The Native Xml Database Dynamic Node Encoding Scheme

With the development of related standard on xml, a great deal of XML documents appeared on internet, how to effectively manage and query these files become an urgent problem,what will greatly promote research on XML database technology. Native XML Database (NXD) is designed to store and manage the XML files whose queries include value inquiries and structure inquiries in NXD. The main ideas to judge structure relationship between nodes is to decompose a complex inquiry mode into several sets of dual basic structure relations. First calculate the basic structure of binary relations, and then match the basic combined. In such strategy, to caculate the basic structure relations (including parent-child and ancestor-descendent relations) become the key operations of query processing, and the operations is defied structure connecting (or contains connections). The establishment of various indexing can improve structure linking algorithm's efficiency, various indexes can be easily set up by XML nodes coding. Therefore, a large number of scientific research workers concentrate on XML document node coding studies.In this paper, analyze dynamic nodes coding scheme in original XML database and its application for a thoroughly,on the basis of that emphasize on the research of three dynamic coding schemes, that is ORDPATH coding, coding and DLN DeweyIDs coding and develop a software about three codding shema with c sharp. Use ten standard XML documents test sets to exam further, what will come out some test results by which I analyze and compare of the three codings' accuracy, dynamic and compression; Next, I analyze the dynamic coding scheme's performance on theory. In its all performance, I emphasize on compression whose standard is compute the storage space that coding K layer totem. Use the fixed length, the length domain, prefix code and control token to encod K layers logo and statistic the storage space occupied by S respectively, and ultimately achive about S and K's general formula.At last, discuss the application of dynamic node code schema in query plan and query processing model.