Space debris is very dangerous to the security of on-the-orbit spacecrafts, and it is increasing in number at high speed with the expansion of human space exploration. Space debris has become a serious space pollutant...Space debris is very dangerous to the security of on-the-orbit spacecrafts, and it is increasing in number at high speed with the expansion of human space exploration. Space debris has become a serious space pollutant noticed by many astronomers. The increase of space dust sources and the development of research on space dust urgently need space dust data sharing and exchanging. It is necessary for us to establish the Space Dust Database to realize the sharing and canonical management of the data. The Space Dust Database (SDD) management system, based on the 3-layer B/S computer mode, was designed and implemented in this paper. The system’s features include significantly improved runtime efficiency, good scalability and maintainability. The Space Dust Database can provide some scientific bases for the study of the chemical constituents, mineral composition, origin and sources of space dust, but also provide excellent data services and decision-making support for the protection of space and model construction of space dust.展开更多
为了解决实体书店受到服务时间、地理位置以及启动资金大等条件制约的问题,设计了一个网上书店系统,该系统基于用户层/应用层/数据层的三层模式体系结构设计,使用Visual Studio 2005平台结合SQL Server 2000数据库进行开发。经试验证明...为了解决实体书店受到服务时间、地理位置以及启动资金大等条件制约的问题,设计了一个网上书店系统,该系统基于用户层/应用层/数据层的三层模式体系结构设计,使用Visual Studio 2005平台结合SQL Server 2000数据库进行开发。经试验证明,本网上书店系统具有功能比较稳定、代码可移植性好和维护简单等优点。在此着重讨论如何设计基于B/S三层结构的网上书店系统,分析了开发系统的关键技术和难点。展开更多
文摘Space debris is very dangerous to the security of on-the-orbit spacecrafts, and it is increasing in number at high speed with the expansion of human space exploration. Space debris has become a serious space pollutant noticed by many astronomers. The increase of space dust sources and the development of research on space dust urgently need space dust data sharing and exchanging. It is necessary for us to establish the Space Dust Database to realize the sharing and canonical management of the data. The Space Dust Database (SDD) management system, based on the 3-layer B/S computer mode, was designed and implemented in this paper. The system’s features include significantly improved runtime efficiency, good scalability and maintainability. The Space Dust Database can provide some scientific bases for the study of the chemical constituents, mineral composition, origin and sources of space dust, but also provide excellent data services and decision-making support for the protection of space and model construction of space dust.
文摘为了解决实体书店受到服务时间、地理位置以及启动资金大等条件制约的问题,设计了一个网上书店系统,该系统基于用户层/应用层/数据层的三层模式体系结构设计,使用Visual Studio 2005平台结合SQL Server 2000数据库进行开发。经试验证明,本网上书店系统具有功能比较稳定、代码可移植性好和维护简单等优点。在此着重讨论如何设计基于B/S三层结构的网上书店系统,分析了开发系统的关键技术和难点。
