Design And Implementation Of Data Access Middleware For A Logging Company

Along with the rapid development of information for the logging company, more and more softwares are developed to provide online information services for the oil field exploration. Most of them are developed independently using different programming language and Database Management System by different departments, so the mode of database access and the method of access control are different. Some applications access to database directly, others get data through some particular data access service softwares. These softwares with similar functions are repeatedly developed by different departments, the efficiency of software development is inevitably reduce. In the aspect of security, the data access control is managed by each software, the security level is determinded by the appliction with the lowest security. How to share resources, shield the differences of heterogeneous databases, change the situation of the original application program visiting database indirectly to enhance the security of the system and improve the efficiency of software development is the main problems for the construction of information of the logging company.The works is a part of the project of a logging company. The aims of this work is to design a uniform data access middleware to provide unified data access services and access control services for the applications.Data access middleware technology, XML technology, Socket programming and database connection pond and other relevant basic knowledge are analysised in this paper. According to the actual requirements, the overall model and functions, data access and access control, of the data access middleware are proposed. The design and implementation of data access module is mainly introduced in this paper.Data access module can be devided into two parts, which are application interface module and data access agent module. The application interface module will provide a unified application programming interface for applications to access to database. The data access agent module will coordinate various heterogeneous database systems and shield complexity and diversity of underlying environment.The communication between the application interface and the data access agent is achieved by using Socket technology based on TCP, data are tranferred in XML format. In order to improve the response speed and support multi-user concurrent access, thread pool technology and connection pool technology are used.