Application Of The Database Replication Technology In Automatic Monitoring System

Based on air quality automatic monitoring system for example, this paper expounds the application of the database replication technology in automatic monitoring system. Air quality monitoring systems can help us to master the trends and changes about environment air quality, extremely helpful to people's livelihood. It includes the monitoring central station and the sub monitoring stations, the sub monitoring stations locate throughout the urban areas, the data stores in a distributed environment. In order to merge and backup sub-station data, the database replication technology is applied. The database replication is divided into the replication process and the revision process. The replication process is consisted of four steps: changes capture, distribution, synchronization and conflict detection and resolution. Five methods are used to capture changes: the snapshot method, the log method, the API method and the timestamp method. These five methods of capturing changes are introduced. According to the distribute server position, the distribution is divided into: push mode, pull mode and push-pull mode. Usually, conflict detection and resolution is based on the actual situation.This paper is based on the database synchronization module of the Project "The construction of Wuhan environment air quality monitoring system". According to the actual needs, the merge replication of SQL Server is chose as synchronous solution. The wizard method of merge replication, batch and replication programming method are experimented. A replication component is developed by c #.net, and uses Indusoft built a test platform, then carries on the test. By the above three methods of experimental comparison, concludes: for the deployment of multiple sub-site replication, batch processing and development of replication component is better than the wizard method.