【作者】 蒲斌；

【导师】 余立建；

【作者基本信息】 西南交通大学 ， 通信与信息系统， 2005， 硕士

【摘要】 随着移动通信技术和互联网技术的迅速发展,人们需要能在任何时候、任何地点无线访问所需要的数据。由于移动计算环境复杂多变的因素,传统的分布式数据库不能有效地支持移动应用的数据访问需要,移动数据库技术应运而生。如何以传统的分布式关系数据库技术为基础,构建适用于无线网络环境的移动数据库成为分布式数据库研究领域中一个重要的问题。 论文对移动数据库技术的发展现状进行了广泛论证,深入研究了移动数据库的典型系统模型,讨论了移动数据库系统体系结构、特点及其应用前景,移动数据库的关键技术,并针对数据复制提出了一种基于双向异步复制的数据一致性解决方案。将传统分布式系统的数据复制方法与移动数据库系统的特点相结合,利用基于分布式关系数据库的事务日志表和数据广播技术,来实现移动客户端和服务器端后台数据库系统间的双向异步复制。方案中存在上行和下行两条数据链路,上行链路从移动结点指向基结点服务器,负责把移动结点的事务日志表复制到服务器;下行链路从服务器指向移动结点,提出了基于访问时间的广播调度算法,用于解决数据广播和数据更新带来的对数据一致性的影响。 系统选择典型的分布式关系数据库SQL Server 2000为基础数据库平台,基于Delphi6.0软件平台,开发了军用器材移动信息系统。经过实践验证,该系统达到了设计要求。 论文最后总结了系统运行的情况,指出进一步需要解决和研究的问题与方向。更多还原

【Abstract】 With the development of internet and mobile communication technologies, it is possible for people to access data anywhere and at anytime. As a more flexible and complex mobile computing environment, traditional distributed database technologies can not support the need of mobile data-access,so mobile database comes into existence. How to construct a mobile database based on traditional distributed database technologies, which can adapt the wireless environment, has been a key problem of distributed database researches.This thesis particularly studies the status of mobile database, discusses architectures, characteristics, some key technologies of mobile database. And the thesis presents a data consistency maintenance solution based on bi-asynchronism data replication technology,which can maintains data consistency in mobile database environment. Combining characteristics of mobile database technologies with traditional duplication methods of distributed databases, bi-asynchronism data replication solution realizes the bi-asynchronism data replication between mobile clients and servers with SQL Server transaction-logs-tables and data broadcasting technologies. There are two links in this solution. As for the up link, it replicates from mobile clients to servers by SQL Server transaction-logs-tables. On the other hand, the down link replicates from servers to mobile clients by the broadcast average visited-time.The thesis designs a distributed application system under mobile computing environment with SQL Server 2000 as basical database flat and Delphi6.0 software,and realizes bi-asynchronism data replication solution in the Design and Application Of Military Device Mobile Information System. Practise proves that system has been realized the aim .Finally the thesis summarizes the running status of the system and shows the direction of the further studies.更多还原