Computational Study, Based On The Prefix Code Orderly Xml Document Update

HTML(the abbreviation of hypertext markup language) is a way of information expression in web, but it can merely define the appearance and form of data. However, some technology of XML (the abbreviation of extensive markup language) not only can define data's appearance and forms, but also defines structure of the data. A contrast between HTML and XML shows that XML is with features of flexibility, simplicity, readability, good expansibility, and standardization, and it has become one of the most important technologies in the Web. Therefore, how to effectively store, examine and process the XML document data becomes a major problem in the XML data management system. At present, the management of XML data based on a particular coding scheme and a certain coding method is a hot issue.Three main factors of judging a kind of fine coding scheme include: (1) coding storage space; (2) code of query performance; (3) whether the coding can support the updated calculation of XML documents or not. The current proposed coding scheme mainly has three types: path coding scheme, interval coding scheme and primes coding scheme. These coding schemes have better performance in the support of inquires. Regretfully, there are some problems unsolved in the existing coding schemes, that is, some can not support the updated calculation effectively, or some can update calculation with high cost, or some will sacrifice the query performance, or some should add the storage space. So, this paper, on the basis of the storage space in control available and not reducing inquires performance, explores a coding scheme which supports the updating and obtains a balance result in query performance, coding space and update performance.Based on the analysis of the current coding schemes and coding methods, this paper proposes a new encoding Scheme, that is, IDLS (improved Dewey Labeling Scheme). This coding scheme can reduce the cost of XML updated documents and maintain query performance, by increasing a small amount of storage space.Main jobs of this paper are as follows:(1) by comparing with the existing coding scheme and coding method, and points out their shortcomings in support of the updated calculating in XML document;(2) proposes a new coding method -- IDLS coding scheme which has a better support for the XML document updated calculation, and will not reduce the query performance, by adding a small amount of storage space simply.(3) analyzes the feasibility of IDLS coding scheme and presents the key algorithms;(4) by experiment, a comparative analysis is made between the IDLS coding scheme and the existing main coding schemes in terms of query performance, storage space and updated performance.