Studies On Data Synchronization Mechanisms And Its Application In Mobile Computing Environment

Benefiting from the development of network technology and mobile communication technology,application based on mobile computing devices becomes more and more popular.Personal Digital Assistants(PDA),mobile phones and so on, are being used to do business wherever.Application data can be downloaded to mobile hand held devices from the remote database system,and can be accessed and updated offline.It synchronizes with the remote database from time to time when the connection is available.Therefore,databases synchronization technology as the times requires,and has become a dynamic and exciting topic.At present because the conditions of network and resources of mobile devices, mobile equipment can not connect network sustaining,the demands of data access can not be satisfied in the disconnected network.The data accessing and processing must be realized urgently no matter in anywhere and at anytime.Mobile database data synchronization method is particularly important.The paper focuses on this issue.The thesis background is PDA mobile levy system,which is the part of maintenance costs of Changjiang waterway vessels management system,the project is the second phase information system of Changjiang waterway vessels department of communications ministry.Focuses on the research of the popular technologies remote data access and merge replication,based on these research works,a kind of realization method is given.The operation perform on the mobile devices and remote database server separately,the unification of data through data synchronization.Because of the separately operation,the data conflict would be happened,time sequence of data is used to solve this problem,the stability of transmission is guaranteed.Data filter is used for data division,such as horizontal filter,vertical filter and dynamic filter.Only the key information storage in devices,the method solves the limitation storage access of mobile devices preferably,the quantity of data is reduced,the speed of processing is improved,and the time of synchronization is reduced.Create subscription in mobile devices by code,it easy for users compare to traditional manual method.At present,the method of data synchronization used in Changjiang waterway department widely.The application proves that this method of data synchronization performs perfect,its get the anticipated purpose.