Study And Implementation On OGSA Based Grid Database Service System

With the rapid development of computer technologies of software and hardware, there are more and more opportunities for all kinds of trades. At the same time people realized that a lot of resources like computational resources and storage resources are left unused and this is disadvantaged for the development of society. Therefore people began to pay attention to grid technologies which can take advantage of excessive resources to help those who need them to finish their works. The target of grid is to achieve the sharing of distributed resources efficiently so that the customers can work harmoniously. The problem that should be first resolved is that how to provide efficient data resources administering functions to support resources and information's discovery in grid environments.This thesis provides a data access and integration method which is based on Metadata Catalogue Management Service and Data Base Broker Service that are based upon OGSA-DAI to carry out the database management system in grid environments which can be integrated well with existing technologies of Web Services.First, based on the concepts of service data in DAI and Metadata, we defined a layered architecture of Metadata that consists of physical Metadata, service Metadata and applied Metadata and mapping relations between them. The added Metadata Catalogue Management brings simple and convenient database accessing method and customers get the result datasets easier than before. The process of accessing and maintaining data resources dynamically becomes more neatly by describing Metadata of physical resources distinctively from Metadata of accessing database resources. This architecture makes the design and implementation of data managing service easier and boosts up expansibility of the whole system.This thesis provides Database Broker Service based on the concept of layered services in DAI according to OGSA. By combining lower services and database service and factory service which create new entities, we build up higher service, Data Base Broker Service. Data Base Broker controls various database resources cooperating withMetadata Catalogue Management Service, and masks the diversity and volatility of various data resources.In order to wrap operations offered by Database Broker Service and Metadata Catalogue Management Service and allow for customers, we provide simple and friendly query services on Web Server. We construct Web Server based on the ideal frame MVC.According to these ideas, we designed Grid Database Service System. The better results acquired through experiments have validated the feasibilities of the project.