Research And Implementation Of Database Notification Service

In today's society, we have enter the information age, we were surrounded by a variety of information, stock quotation, company management, customer relations, weather, sports news... instant access to information is an important work of the development and utilization of information. The information's users always want to be notified when information they interest changed, Some information missing mean economic loss.The information is currently stored and managed by database, database notification service which based Pub/Sub model provide the solution, which changed the mode of information exchange. Database notification service is an active database technology, it can sent the user data of interest to the specific user.Thesis studied the development of database notification service-related technologies, summarized the key issues to achieve the data notification service. On this basis, designed a database notification service architecture, and detailed analysis the module functions of the structure, described the main issues to be resolved in the modules. This article compared the data capture method before, these methods' efficiency is not high, and only support single environment, combined with the advantages of different methods and proposed an effective capture method called FDDNS. The method is more suitable for database notification service environment.The algorithm before for generating complex data model and semantic shortcomings of expression is not strong, thesis study an event matching algorithm in content-based publish/subscribe data model, the algorithm reduce the number of repeat matches through a multi-level indexing, and enhanced semantic data model expression through two-stage matching algorithm on the composite subscription matching conditions.Thesis implements a prototype database notification service in.NET platform, and applied in Laoshan strobe and green channel monitor system. It verify the validity of the proposed system, and improve the database notification service configurability and scalability using reflection.