The Study Of Metadata Management Based On G/S Mode Servers

Informationization is one of the most important means to advance the development of society. Currently, modern information technology which makes computer technology, communication technology and network technology as representatives let human beings use of information recourses into a modern stage of efficiency, profession, diversity and share. Since Information has become an important core of development of productive forces and national strategic recourses, the organization and management complexity of large data producers and users are becoming the most prominent problem. That is to say, the data producers need effective data management and maintenance methods; the users need to find a faster, more comprehensive and effective way to find, access, access to and use the dates that is of high potential, high precision, easy management and easy accessing. Under these circumstances, the content, quality, condition and other metadata information of the data become more and more important, which become of an important means of effective management of information recourses and application. U.S. Vice President, AI Gore, also make meta-data as one of the important supporting to Digital Earth during his"Digital Earth"speech.Firstly, on the basis of the analysis of G/S cluster of servers distributed spatial information, the paper introduced the theories of G/S model, including the systemic model, characteristics, advantages, and key technology of G/S model. Then, on the basis of introducing HGML technology, the paper focused on the analysis of the concept, features of HGML and the technology of analytic and query about HGML. At the same time, the paper analyzed the status quo, functions and meaning of the metadata in nowadays, but the definition of metadata is not unified, yet. According to the need of practical item, the paper designed the basic content about metadata. The text proposed the general framework of organization and management about metadata In accordance with the present G/S model of distributed spatial data servers. Then bases the characteristics of general framework, the paper used Socket communication technology, combined with multi-threading programming, and designed a prototype system which aimed at the organization and management of metadata under the distributed spatial data servers about G/S. Finally, the paper achieved the update of metadata on the basis of prototype system.The achievements are embodied in the following. There are 4 aspects. Firstly, according the G-side need of G/S model and the definition of metadata,the paper designed the basic elements of metadata; Secondly, the paper introduced the HGML to achieve the organization and management of metadata under the G/S model;Thirdly, among the distributed spatial data servers , the paper designed the prototype system of metadata's organization and management according to the use the single Master node to manage MetaDataServer node;Fourthly, the paper achieved the update of metadata on the basis of HTTP principle and also in the realization of prototype system.