Design And Implementation Of Middleware For XML Databases

SaaS software service pattern transforms discrete software purchase model into software rental model. The user can customize database according to their characteristics and needs flexibly. The development of middleware lights the fusion among the heterogeneous software architectures. It can availably wrap to different database system's methods and interfaces, provide several public interfaces for its client to visit the distributed databases in the heterogeneous platform. Because of the XML database dynamically expansion, its volume of platform is not limited. This database provides relatively cheaper design and storage platform, so that users need only what they actually will consume, leading to the need for the research. Hence, XML database is referred to as perfect partner for SaaS.The research based on the XML database middleware design and application is proposed in this paper. The middleware will facilitate procedures for the use of XML and relational database access in both directions. Firstly, the XML databases features, advantages and development trends are examined in the article. And also, a variety of independent application software, WEB database (reflected in the data collection and dissemination), and the more frequently use of XML format in heterogeneous database integration are noted. Finally, the XML is compared with the relational database and their relationship when it is used for data storage and expression.The middleware for XML databases is designed in this project. From the perspective of heterogeneous integration, it utilizes XML, CORBA and Java technology by using XML as the common data model to provide users a unique search interface. The following main modules are designed in this article:the client adapter and communication, user and connection management, control modules, compression decompression, XML and relational database schema mapping and data migration. The application is considered basing on the application requirements and middleware features flexibility. And the characteristics and advantages of XML database middleware are compared with other database middleware. The module based on the implementation of JAVA is expounded in detail, such as:system configuration management module, communication adapter threads, thread control, system management and monitoring process, buffer management modules and mapping mode.