学生学籍管理系统设计与开发

学生学籍信息管理系统是典型的管理信息系统,其开发主要包括后台数据库的建立和维护以及前端应用程序的开发两个方面。对于前者要求建立起数据一致性和完整性强、数据安全性好的数据库。而对于后者则要求应用程序菜单界面友好,功能完备,易操作等特点.     

基于Web和数据库的网络管理系统的设计与实现

提出了一个基于Web和关系数据库的网络管理系统的管理模型,并描述了一个基于该模型的网络管理系统——Super-Domain的组成结构及其具体实现机制.讨论了系统实现中的关键技术问题及其解决方法,其中包括管理信息的存储模型、数据一致性维护、基于Web的实时告警机制、系统安全机制等.     

移动数据库的同步管理技术的研究

文中结合在实验室自行开发的移动数据库原型SwiftDB，介绍了移动数据库系统的发展现状，提出了基于两级复制模型的同步解决方案双向复制，并根据不同应用环境采用不同方法加以实现，在维护数据一致性的同时也提高了系统的性能。     

基于Web Service的数据一致性维护方法

随着互联网和分布式数据库系统的广泛应用,如何保证多个数据库之间的数据一致已成为系统可靠运行所要解决的重要问题。而Web Service可以通过HTTP、SOAP（XML）等协议为互联网用户提供服务,具有良好的普适性和灵活性。提出了一种基于Web Service的数据一致性维护方法,并实现了相应的同步一致和异步一致的维护方法。该方法不仅适用于各种分布式数据库,也可应用于相互独立的多个数据库。     

校园网上选课系统

系统开发设计的目的是为了让学生能随时随地通过网络进行选课,为此进行了教务模块、教师模块和学生模块的需求分析,系统共设有三个子模块:学生选课模块、教师管理模块、教务管理模块.其中本文对三个模块进行了详尽的分析,介绍了其设计思想,实施方法,数据库开发、系统实现与应用等相关信息,并匹配了相应的功能实现界面等.最终完成各模块的功能,具体实践网上选课系统.本系统的是一个信息管理系统(MIS),其开发主要包括后台数据库的建立和维护以及前端应用程序的开发两个方面.对于前者要求建立起数据一致性和完整性强、数据安全性好的库,而对于后者则要求应用程序功能完备,易使用等特点.     

2DCMA: An Effective Maintenance Algorithm of Materialized Views in Peer Data Management Systems

Update management is very important for data integration systems. So update management in peer data management systems （PDMSs） is a hot research area. This paper researches on view maintenance in PDMSs. First, the definition of view is extended and the peer view, local view and global view are proposed according to the requirements of applications. There are two main factors to influence materialized views in PDMSs. One is that schema mappings between peers are changed, and the other is that peers update their data. Based on the requirements, this paper proposes an algorithm called 2DCMA, which includes two sub-algorithms： data and definition consistency maintenance algorithm% to effectively maintain views. For data consistency maintenance, Mork＇s rules are extended for governing the use of updategrams and boosters. The new rule system can be used to optimize the execution plan. And are extended for the data consistency maintenance algorithm is based on the new rule system. Furthermore, an ECA rule is adopted for definition consistency maintenance. Finally, extensive simulation experiments are conducted in SPDMS. The simulation results show that the 2DCMA algorithm has better performance than that of Mork＇s when maintaining data consistency. And the 2DCMA algorithm has better performance than that of centralized view maintenance algorithm when maintaining definition consistency.     

基于SQL Server的财务管理系统的自动化异地备份

数据库备份是数据库安全的重要保证。以天财高校财务管理系统为例,分析其后台SQL Server为数据库的数据构成及变动情况,提出每天中午和下午分别对账务和收费的当前数据库进行两次自动异地备份的策略,并利用SQL Server的数据库维护计划功能和文件同步软件Second Copy来实现备份。     

资产管理系统设计与实现

本系统的功能为建立资产数据库,编程实现了资产数据库动态化管理。具有以下优点：1．自动建立数据库。2．灵活的查询功能。3．可方便地对数据库文件进行合并,添加、修改、删除数据库记录。4．具有三种格式的输出功能,即：把数据库文件转化成Excel表打印、设备入库单打印,打印设备标签。5．该软件的查询输出功能和设备标签管理功能可实现资产管理准确、省时、一步到位。在清产核资时可减少大量时间,提高工作效率。6．具有通用性,可适应性,易于扩充、操作和维护。     

资产管理系统设计与实现

本系统的功能为建立资产数据库,编程实现了资产数据库动态化管理。具有以下优点:1.自动建立数据库。2.灵活的查询功能。3.可方便地对数据库文件进行合并,添加、修改、删除数据库记录。4.具有三种格式的输出功能,即:把数据库文件转化成Excel表打印、设备入库单打印,打印设备标签。5.该软件的查询输出功能和设备标签管理功能可实现资产管理准确、省时、一步到位。在清产核资时可减少大量时间,提高工作效率。6.具有通用性,可适应性,易于扩充、操作和维护。     

Performance evaluation of snapshot isolation in distributed database system under failure-prone environment

Database systems are widely used in many fields. As the scale of database systems increases, more firms decide to deploy the database system in a distributed environment for the sake of data integrity fault tolerance. For guaranteeing the consistency of data, database management systems adopt isolation policies. This paper discusses probabilistic models for snapshot isolation of database management system. Snapshot isolation is an effective method to enhance the consistency of database system, although it degrades the system performance where the system has large network latency such as distributed database system. Also, under the failure-prone environment, a restart scheme is considered as one countermeasure. This paper proposes probabilistic models for the dynamics of snapshot isolation of database system and exhibits the optimization of system performance with respect to updating interval of snapshot isolation within the failure-prone environment from the analytical point of view. Numerical experiments are conducted to validate the effectiveness of analytical results by using real traffic data.     

集群数据库系统的日志复制和故障恢复

互联网、社交、购物、金融等各类应用直接面临海量用户的高并发访问,传统的单点数据库逐渐成为这些应用系统的瓶颈,而众多互联网应用能够良好运行的主要原因是使用了基于集群环境的数据管理系统作支撑。与传统数据库系统相比,基于集群环境的数据库系统具有更好的扩展性和可用性,而日志复制是保证这些特性的核心组件。传统的主备架构的日志复制在异常情况下对未决事务日志处理不佳,导致数据副本之间存在不一致的风险,另外,分布式系统领域的一致性算法缺乏对事务一致性的处理,而且在选主时存在活锁、多主和频繁选主的问题,无法直接适用于事务日志复制。本文提出了一种集群环境下的事务日志复制策略和恢复机制,能够有效处理未提交日志,提供了强弱两种读一致性,并且提出了一种轻量级的选主算法,可以避免以上的选主问题。本文在开源OceanBase分布式数据库系统中实现了上述机制,并使用基准测试工具对系统进行测试,通过一系列实验验证了系统的扩展性和可用性。     

Design and implementation of an Interoperable Object Platform for Multi-Databases

In this paper,the authors present the design and implementation of an Interoperable Object Platform for Multi-Databases(IOPMD).The aim of the system is to provide a uniform object view and a set of tools for object manipulation and query based on heterogeneous multiple data sources under client/server environment.The common object model is compatible with ODMG2.0 and OMG‘s CORBA,which provides main OO features such as OID,attribute ,method,inheritance,reference,etc.Three types of interfaces,namely Vface,IOQL and C API,are given to provide the database programmer with tools and functionalities for application development.Nested transactions and compensating technology are adopted in transaction manager,In discussing some key implementation techniques.Translation and mapping approaches from various schemata to a common object schema are proposed.Buffer management provides the data caching policy and consistency maintenance of cached data.Version management presents some operations based on the definitions in semantic version model,and introduces the implementation of the semantic version graph.     

基于图形对象的一致性维护问题的研究

针对实时协同图形编辑系统中一致性维护关键问题,提出了一种基于图形对象的并发控制算法。该算法扩展了面向文本编辑的分布式操作转换dOPT算法,满足图形对象属性级上数据一致性维护,同时通过预定义图形对象间的关联关系和位置属性约束规则,进行操作语义维护管理,使得实时协同图形编辑系统的一致性维护更为有效和完备。     

基于数据驱动的大型数据库设计与实现

CIMS中工程应用数据库系统涉及到多个工程数据库管理系统以及非工程数据库管理系统的互联与集成,它可分解为若干个应用信息分系统和支持这些应用分系统之间信息交换与共享的支撑系统。基于异构的数据系统和文件管理,借鉴NIST技术,采用OO方法和语义关联数据模型,设计了一个面向对象的工程数据库模型及其软件结构,实现了数据的正确交换与共享,并确保全局数据的一致性、完整性和安全性。为构建大型数据库系统提供了一个可行的解决方案和技术支持。     

Improving the performance and functionality of Mondrian open‐source OLAP systems

For a long time, the design of relational databases has focused on the optimization of atomic transactions (insert, select, update or delete). Currently, relational databases store tactical information of data warehouses, mainly for select‐like operations. However, the database paradigm has evolved, and nowadays on‐line analytical processing (OLAP) systems handle strategic information for further analysis. These systems enable fast, interactive and consistent information analysis of data warehouses, including shared calculations and allocations. OLAP and data warehouses jointly allow multidimensional data views, turning raw data into knowledge. OLAP allows ‘slice and dice’ navigation and a top‐down perspective of data hierarchies. In this paper, we describe our experience in the migration from a large relational database management system to an OLAP system on top of a relational layer (the data warehouse), and the resulting contributions in open‐source ROLAP optimization. Existing open‐source ROLAP technologies rely on summarized tables with materialized aggregate views to improve system performance (in terms of response time). The design and maintenance of those tables are cumbersome. Instead, we intensively exploit cache memory, where key data reside, yielding low response times. A cold start process brings summarized data from the relational database to cache memory, subsequently reducing the response time. We ensure concurrent access to the summarized data, as well as consistency when the relational database updates data. We also improve the OLAP functionality, by providing new features for automating the creation of calculated members. This makes it possible to define new measures on the fly using virtual dimensions, without re‐designing the multidimensional cube. We have chosen the XML/A de facto standard for service provision. Copyright © 2008 John Wiley & Sons, Ltd.     

Managing Information in a Co-operative Object Database System

The paper describes a software infrastructure that was built to manage information in a co-operative environment for the design of control systems. The architecture of the environment, the organization of the design database and a suite of information management tools are presented. The paper suggests that the distributed client–server architecture and object database technology meet the requirements of managing information in the environment. The following issues related to information management are examined in more detail: support for version control, maintenance of information integrity by means of object access control and consistency control, support for user co-operation based on object sharing and change notification, graphical user interfaces, and design tool interfaces. Problems encountered during the implementation of the environment using a commercial object database management system are also discussed.     

A Scalable Asynchronous Cache Consistency Scheme (SACCS) for mobile environments

In the literature, there exit two types of cache consistency maintenance algorithms for mobile computing environments: stateless and stateful. In a stateless approach, the server is unaware of the cache contents at a mobile user (MU). Even though stateless approaches employ simple database management schemes, they lack scalability and ability to support user disconnectedness and mobility. On the other hand, a stateful approach is scalable for large database systems at the cost of nontrivial overhead due to server database management. We propose a novel algorithm, called Scalable Asynchronous Cache Consistency Scheme (SACCS), which inherits the positive features of both stateless and stateful approaches. SACCS provides a weak cache consistency for unreliable communication (e.g., wireless mobile) environments with small stale cache hit probability. It is also a highly scalable algorithm with minimum database management overhead. The properties are accomplished through the use of flag bits at the server cache (SC) and MU cache (MUC), an identifier (ID) in MUC for each entry after its invalidation, and estimated time-to-live (TTL) for each cached entry, as well as rendering of all valid entries of MUC to uncertain state when an MU wakes up. The stale cache hit probability is analyzed and also simulated under the Rayleigh fading model of error-prone wireless channels. Comprehensive simulation results show that the performance of SACCS is superior to those of other existing stateful and stateless algorithms in both single and multicell mobile environments.     

基于关系型数据库的CA系统

当PKI技术应用于企业或政府信息化时，它必须与其它业务系统集成。采用与业务系统相一致的关系型数据库，有利于不同系统的集成。当CA系统采用关系型数据库和浏览器／Web应用服务器／数据库服务器3层结构时，证书相关信息的查询可以通过HTTP协议简单实现，LDAP和OCSP引擎可以使系统与标准协议保持兼容。另外，在这种结构下，通过引入基于关系型数据库的角色、权限管理机制，可以大大简化CA/RA的管理，使系统的运行和维护更加容易。     

网上作品展示平台设计与实现

为了给有创作兴趣者提供一个作品展示和相互交流的平台,设计了一个便捷的、淘宝式的作品展示平台。经过需求分析和功能分析,进一步确定了系统主要包括后台数据库的建立和维护,以及前端应用程序的开发两个方面。对于前者要求数据一致性和完整性强、数据安全性好的数据库;而对于后者则要求应用程序功能完备,操作简单等特点。     

支持大数据管理的NoSQL系统研究综述

针对大数据管理的新需求,呈现出了许多面向特定应用的NoSQL数据库系统。针对基于key-value数据模型的 NoSQL 数据库的相关研究进行综述。首先,介绍了大数据的特点以及支持大数据管理系统面临的关键技术问题;然后,介绍了相关前沿研究和研究挑战,其中典型的包括系统体系结构、数据模型、访问方式、索引技术、事务特性、系统弹性、动态负载均衡、副本策略、数据一致性策略、基于flash的多级缓存机制、基于MapReduce的数据处理策略和新一代数据管理系统等;最后给出了研究展望。