The Design And Implementation Of Marine Information Metadata Directory Services System

Along with the development of computer network and information incorporate deeply, the requirement of sharing marine data more and more urgently. On the one hand, the user wishes to acquire marine information data rapidly which is integrated and desirable. On the other hand, there are abundant but scattered marine information resource existed at present, both of this had conflict. As a result, in order to make full use of marine data in existence sufficiently, enhance the usage efficiency, reduce expensive cost for more and more data creator and data user, a sort of data frame mechanism is needed to implement release, share, query and searches effectively.Metadata is the description of information resource standardization; it provides a solid and simple method for information management, discovery and acquirement. People could comprehend information resource in detail and deep through metadata, including information resource format, quality, dispose method and acquire method and so on. Directory is a database for optimize read operation, which is a tree like level structure and provide unify denominate, description, and orientation for various information resource in an organization. Directory services offer a uniform listing, the network system manage various information resources centralized in network. This paper is based on lucubrate the correlated technology of metadata and directory services, combine both characteristic and establish a metadata directory services system, aim to provide reliable marine information metadata for conform various marine information resource efficiently and realize the share and exchange of distributed excessive fountain marine information.Metadata standard and technology is one main method of implement data discovery, management, share and integrity efficiently. First of all, science database could use metadata standard and technology to describe and release data resource in existence, which would improve usability and utilize rate of data. Secondly, metadata record the establishment, structure and maintain information of related metadata, data manager also use this metadata to manage data resource effectively, and data user could understand some background of data resource according to metadata. Thirdly, the usage of metadata is capable of eliminating semantic independence and isomer of data resource in a certain extent, it helps implement the integrity and exchange of data source. This paper set up a suit of metadata standard frame which is fit for marine information, and on the basis of this, the design of metadata directory services system collective frame is established. The system is composed of data layer, operation layer and client layer, data layer is to research storage strategy of XML documents, the marine information metadata storage based on XML format is designed and implemented. In the operation layer, we design the directory mode and tree like structure which combines the classify of marine data, and establish directory information base to memory core metadata data, through JavaBean and DSML to communicate with LDAP directory server, and then the operation layer could search directory metadata promptly and precisely according to client requirement, and obtain the total metadata from metadata base.The draw of marine information metadata standard make data process standardization, it enhances marine data source standardize, strengthen data communication and sharing. Metadata directory services system provides support for exchanges of marine data; therefore, promote the development of marine information.