【作者】 赖鸿斌；

【导师】 李永树；

【作者基本信息】 西南交通大学 ， 大地测量学与测量工程， 2003， 硕士

【摘要】 20世纪末，随着计算机、网络等技术的不断发展，计算技术也逐渐从集中式环境向分布式环境发展。在此过程中，分布式网络计算概念和各种分布式计算模式被相应地提出来。在众多的分布式计算模式中，多层分布式C／S结构模式已经越来越多地被应用在各种具体大型分布式应用系统的设计和开发中，并取得了一定的成效。 本文从分布式多层应用系统的体系结构入手，首先论述了传统两层结构应用系统的缺陷和不足，从而引出了分布式多层结构。接着对分布式多层结构应用系统中的关键技术——分布式多数据库系统技术，进行了深入的论述和探讨，并给出了基于这一技术之上的相应的三层分布式C／S结构模式的铁路工务地理信息系统查询子系统的结构模型。最后，利用达成铁路线路上所采集的部分现有数据和资料，围绕构建分布式应用系统的设计原则，着重探讨了多层分布式应用技术在三层C／S结构模式铁路工务地理信息系统中的具体实现方法，并利用Borland公司的Delphi开发工具、MicroSoft公司的MS_Access小型数据库以及MapInfo公司的MapX图形组件，对本系统的客户端、应用服务中间层和数据服务层进行了具体的开发。相对于铁路工务部门一些传统的信息系统，本文所开发的基于三层分布式C／S结构模式的铁路工务地理信息系统具有较好的先进性，对今后铁路地理信息系统的开发和建设具有一定的参考价值，为后续此系统的进一步深入研究和开发，打下了良好的基础。本系统的主要模块和功能有：①用户登录管理模块，用来对进入系统不同用户进行身份的验证，从而对系统的安全进行维护和管理。由于本系统是基于三层C／S结构模式的铁路工务地理信息系统，因此，用户登录管理模块可进一步分为远程服务器登录模块、远程数据库登录模块和客户端用户登录模块。②查询统计模块，可完成各工务段、各车站的设备查询和统计输出等。本系统的查询统计模块主要包括有线路沿线设备查询、全线车站查询、全线设备统计和全线各车站信息统计等。③图形操作模块，利用图形组件MapX和Delphi可视化开发工具实现了达成铁路线路平面图、达成铁路各车站平面图的图形操作功能。④属性管理模块，实现系统数据表(如各车站表、桥梁表、隧道表等)的管理和维护，如属性表的 西南交通大学硕士研究生学位论文第n页浏览、备份等。⑤报表输出模块，利用Delphi的QuickRePort控件实现系统工务设备、人力资源等的报表输出。⑥系统维护模块，主要包括系统的安全性和稳定性设计。 另外，本文还对系统具体设计和开发过程中的一些技术问题和难点，如数据库的管理、系统自定义接口、数据绑定以及系统的性能优化和安全机制做了深入的分析和研究，并给出了相应具体的解决方法。·更多还原

【Abstract】 At the end of 20th century, with the development of technology of computer and network, computing environment was trending towards distributed from centralizing. During this period, the conceptions of distributed network computing and all kinds of distributed computing modes were put forward. Among these modes, multi-tier distributed Client/Server structure mode has been widely adopted in the large-scale application system’s design and exploration, and some results were achieved in these systems.Starting with the framework of the multi-tier distributed Client/Server application system, the limitation and shortages of the traditional two-tier structure are firstly discussed, and the multi-tier distributed structure is consequently introduced. Then the key technique of the multi-tier distributed structure application system, distributed mutil-database system technique, is deeply dissertated and discussed, and three-tier distributed Client/Server structure model of the RGIS based on this technique is presented. Finally, using a part of present data collecting from the DaCheng railroad and based on the devising rules of constructing the distributed application system, we emphatically discussed the concrete implementing methods using distributed mutil-tier application technique in railroad Gongwu information system of Client/Server structure, and what’s more, do some work on the development of the client, middle-tier of application server and the tier of database server of the system by using the Delphi developing tool (the Borland company), MS_Access (the Microsoft company), and the graph components MapX (the MapInfo company), and so a part of functions of RGIS are realized. Compared with the traditional information systems of the Railway Gongwu department, the Railway Gongwu Geographic Information System based on three-tier distributed C/S structure mode has its advance and reference value for the later development and construction of the RGIS, as well as makes a favourabal foundation for the further deep study and development of the system.The main modules and functions of the system include: (1)User logging on module,different user’s identification can be validate before entering the system for the purpose of maintaining and administering the security of the system. Since the system is based on the Railway Gongwu Geographic Information System with the three-tier C/S structure mode, it can be further divided remote server logging on module, remote database logging on module and client user logging on module. (2)Querying and Statistic module, equipment inquiring and statistical output for every Gongwu section and railway station can be performed. The querying and Statistic module of the system mainly include equipment querying, railway station querying, equipment statistic and every railway station information querying for the whole railway. (3)Graph manipulating module, the graph operating function for the railway ichnography and stations’ ichnography of Dacheng railway using visualizing developing tool Delphi and MapX can be implemented. (4)Attribute managing module, the management and maintenance for the system data tables(eg. station tables, bridge tables and tunnel tables ) are achieved. (5)Report forms outputting module,using the component QuickReport of Delphi to output the report forms of system equipment and manpower resources. (6)System maintaining module, mainly involving system security and stability devising.Additionally, some key techniques and difficulties of devising and developing system, such as database management, the user-defined interfaces of system, data binding, the performance optimization and security mechanism for system, are thoroughly analyzed and studied, and the concrete solving method is also given in this paper.更多还原