用“对号入座”法开展SQL查询语句的教学

对于初学数据库的学生而言,SQL查询语句是他们走进数据库世界必须通过的大门之一,也是＂门槛＂较高的大门之一。如何使用简单的命令来完成复杂多变的查询成为困扰学生的一个难题。该文从解决SQL查询语句的入门学习难点入手,详细介绍了如何让学生利用＂对号入座＂法来编写SQL查询语句。     

ASP.NET网站设计中SQL注入式攻击的防范策略

1.SQL注入式攻击的原理及危害1.1注入式攻击的概念所谓SQL注入式攻击,就是攻击者利用设计上的漏洞,在目标服务器上运行Sql命令,把SQL命令插入到Web表单的输入域或页面请求的查询字符串,欺骗服务器执行恶意的SQL命令,或以及进行其他方式的攻击。     

VFP中巧用查询设计器设计复杂查询

SQL是结构化查询语言Structured Query Language的缩写,其中查询是SQL语言的重要组成部分。SQL已经成为关系数据库的标准数据语言。Visual FoxPro也将其融入到自身的语言中,可以直接以命令方式交互使用,也可以嵌入到程序中以程序方式使用。这些使用方式,为用户提供了灵活的选择余地。尽管SQL的使用方式不同,但SQL语言的语法基本是一致的。SQL的核心是查询,它的查询命令也称作SELECT命令。     

一种交互式关系代数学习工具设计

关系代数查询、查询优化及转换为等价SQL语言是高校计算机相关专业的核心课程,也是数据库系统课程教学中的重要内容。查询表达、优化、与SQL语言之间转换的工作原理很难被学生直观地理解和掌握,因此学生认为关系代数在关系型数据库的实际执行中没有发挥重要作用。该文基于LALR(1)文法实现了一个界面良好、操作简单的关系代数学习工具。该关系代数学习工具允许通过使用图形界面连接关系型数据库管理系统(例如SQL SERVER),建立关系代数表达式,对关系代数表达式进行对错判断,实现查询数据的实时反馈,让学生更好地理解和学习关系代数。此工具已应用于该校计算机相关专业数据库系统的课程教学,取得了良好的效果。     

WEB环境下作业提交与查询功能的实现

针对传统作业批改方式周期长、问题反馈解决不及时的缺点,使用ASP技术设计基于WEB的作业提交与查询系统。所提系统主要由管理模块、教师模块、学生模块等组成,具备身份验证、学生作业提交、WEB数据库访问等功能。数据库使用SQL SERVER 2000,通过ASP内置的数据库访问组件ADO对数据库进行访问,可以实现教师作业提交和学生作业查询等功能,是提高教学效率、减轻教师批改作业强度的有效工具。     

基于SQL的自助数据分析模式设计

针对集成报表难以满足多样化的数据分析需求,设计并实现一种基于SQL Select的自助数据分析模式.该模式通过在用户层数据别名与物理数据库之间、在分析选项与SQL指令之间建立映射关系,设计相应算法完成数据解释、数据关系解析、查询逻辑判定、语法逻辑判定,并根据解析和判定结果完成Select指令重构和数据查询分析:完整地构建了数据查询分析的自助模式设计,使普通用户能够完成自定义的数据统计分析,有效地增强信息系统数据分析能力与决策支持能力.     

基于SQL注入攻击的三种防御技术

SQL注入攻击是基于ASP/ASP.NET+ACCESS/SQL Server架构的Web应用程序和数据库系统,将非法的SQL命令语句通过正常的数据传递渠道提交至数据库内部执行,从而达到篡改、破坏数据的目的.针对此,三种基于SQL注入攻击的防御技术:参数化查询、存储过程和URL重写,通过实例来验证和比较它们的防御效果,为合理选择使用、提高Web应用程序的安全性提供一定的参考和借鉴.     

基于工程数据库的虚拟机开发模式

针对工程数据库管理系统的实际需求,在设计实现基于Web的工程数据库管理系统EDBMS的SQL语言系统时,提出了一种以逻辑分层为基础的系统开发模式——虚拟机模式。该模式由Web Server将用户在浏览器端输入请求命令组装成标准SQL语句,并将这些语句传递给解释器,由解释器进行词法分析、语法分析和错误检查后生成底层EDBMSAPI能够执行的命令序列,从而实现了对数据库的操作。     

VFP查询命令SELECT-SQL在多表查询中的应用

本阐述了SELECT—SQL查询命令在多表查询中的应用，并介绍如何将查询的去向在列表框、表格、本框中显示三个方面应用实例，也介绍了视图在多表查询中在这三个方面的应用。     

基于Echarts学生成绩管理系统设计

介绍中、小型网站开发的基于Echarts学生成绩管理系统,该系统使用ASP.NET编程工具以及SQL Server数据库实现对学生信息、学生成绩及考试信息的查询和管理,并能通过Echarts技术对获得的关系数据以动画形式进行展示。     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

Western and Eastern culture differences in commercial field

The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity.     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

风的曲线

Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.