Through the research on database application in cad by the author , a concept named central database ( cdb ) is posed , a cdb is planned and built , a central database management system ( cdbms ) and its development tools are developed with object oriented design ( ood ) method on the basis of autocad sql interface ( asi ) , and the object oriented extension of the rational database system is researched 作者研究了数据库在cad中的应用，提出了中心数据库的概念，规划并建立了一个中心数据库，并在autocad的sol接口( asi )基础上，应用面向对象的设计思想开发了中心数据库管理系统及其开发工具；研究了关系数据库的面向对象扩展技术。
In order to gather and analyse the load information automatically and promote the level and precision of distribution network plan , line loss analysis and operation mode adjustment , the data from distribution measuring devices , load supervising system and automatic message registering are centralized through mapping in dgis ( distributuin geography information system ) and other three systems 摘要为实现对配网中负荷的自动采集和分析，以提高配网规划、线损分析及运行方式调整的水平与精度，采用中心数据库数据集中方式将配电综测仪、负控系统和抄表程序数据集中管理。
Because different network operating systems and applications store their own information in different location , information ca n ' t store in a center database , which make administration and maintenance more difficult . it is directory service that resolved this sort of difficulty by means of information ' s centralized storage 不同网络操作系统和不同应用程序分散存储着大量信息，信息无法集中存储在一个中心数据库中，加重了管理员管理和维护的负担，目录服务则通过信息的集中存储解决了现实中面临的管理和维护的困难。
Feature models of products ( parts ) can be built by using the fm system . under the management of the cdbms the models can provide useful information of products or parts to the processes of cad , product data management ( pdm ) , capp and cam , and then can give service to the cad / capp / cam integration 通过特征建模系统可以建立产品(零件)的特征模型，这个模型在中心数据库管理系统的统一管理下可以为cad 、产品数据管理( pdm )以及后续的计算机辅助工艺设计( capp )和cam提供有用的产品和零件信息，为最终实现cad capp cam集成服务。
During the six - month pilot phase , for example , state health inspectors will test the system by entering data from restaurant visits into laptops and sending the information to the health department . emergency workers will test sending patient information from an ambulance while en route to a hospital . graduate students at brown university , a partner in the project , will use the wireless network when teaching public school students 比如，州卫生检察官在餐馆执法时，可以通过联网的膝上型电脑，把有关信息传送到卫生部门的中心数据库中急救工作者可以在送病人去医院的路上，从救护车上发送病人信息给医院，以节省宝贵时间大学研究生则可以通过无线互联网，给公立中学的学生上课。
The operating process of network cipher computer and kdmc are discoursed firstly , then the tcp / ip stack of linux is introduced , and an ipsec realization method with using a cipher card is put forward . triplex key system is adopted for internet key exchange ( ike ) . the database and other modules are also designed and implemented 论文论述了网络密码机和密钥管理中心的工作流程，接着介绍了linux下tcp / ip内核协议栈，提出了加密卡方案，采用了三重密钥管理体系实现了internet密钥自动交换，进行了中心数据库设计与实现，最后对其它模块进行了实现。
Firstly , the paper makes an introduction of develop status , deficiency and its background of onc - card - systcm . secondly , cxpatiation is done on the system structure and function requirements of campus one - card - through system , followed by a description of the appropriate database suitable to campus one - card - through system ; thirdly , the paper puts forward an overall plan of campus one - card - through system including the choice of card , the storage of information in the card , the design of network architecture of the system , moreover , the paper studies a software research mode by combining browser / server and client / server . fourthly , the paper explores the distributed database and the method of its establishment , the paper also attaches great importance to the key technology of distributed database , that is , the coherence , the parallel and security of database 本文首先介绍了一卡通系统的研究现状及课题的选题背景和意义，然后对校园一卡通系统的体系结构、功能需求、采用的数据库进行了分析；提出了校园一卡通系统的总体方案设计：包括卡的选择，卡上信息的存储，系统的网络结构设计，并探讨了一种将b / s和c / s两种模式相结合作为系统的软件开发模式；然后探讨了校园一卡通系统分布式数据为结构及数据分布策略，阐述了分布式数据库中一卡通中心数据库和各子数据库之间的关系及其建立方法，同时对分布式数据库中的关键技术? ?数据的一致性、并发性和安全性问题进行了讨论。
Firstly , it analyses the architecture of mobile database and then provides some studies about data classify , data partition , data replication and cache in mobile client . and after that this paper provides a dynamic strategy to manage the cache of mobile client 接着对移动客户端的数据分类、数据分片、数据复制和缓存的管理，以及移动客户端与中心数据库的数据冲突及与之相关一致性维护进行了一些研究和探索，提出了移动客户端缓存的一种基于优先级和数据分类的动态管理策略。
