数据库系统中的查询技术探讨

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1、毕业设计(论文)题目名称数据库系统中的查询技术探讨院（系）专业班级学生姓名指导老师辅导老师时间目录毕业设计任务书………………………………………………………………………I开题报告……………………………………………………………………………III指导教师审查意见………………………………………………………………IX评阅教师评语………………………………………………………………………X答辩会议记录……………………………………………………………………··XI摘要…………………………………………………………………………XII1前言···········

2、····················································12选题背景……………………………………………………………………………22.1课题的背景及来源…………………………………………………………22.2研究的目的和意义…………………………………………………………22.3国内外发展现状和趋势与研究的主攻方向………………………………33查询优化概述·····················································33.1查询优化的基本概念········

3、···································33.2关系查询语言················································43.3查询优化目标·················································53.4查询处理流程················································64数据库查询优化技术···············································74.

4、1分布式查询优化················································74.1.1分布式查询优化需要考虑的问题···························74.1.2分布式查询优化过程·····································84.1.3分布式查询优化的目标···································94.2查询优化技术················································104.3实例

5、分析····················································125总结·····························································156参考文献…………………………………………………………………………157致谢………………………………………………………………………………16中文摘要数据库系统中的查询技术探讨学生：学院指导老师：学院【摘要】数据库技术是通过研究数据库的结构、存储、设计管理以及应用的基本理论和实现方法，并利用这些理论

6、来实现对数据库中的数据进行处理、分析和理解的技术。即：数据库技术是研究、管理和应用数据库的一门软件科学。查询优化技术是数据库管理系统设计和实现所采用的一项重要技术，也是影响数据库系统性能的一个重要因素，当前所有商用数据库都成功采用了这项技术。关系数据库系统和非过程化的SQL语言能够取得巨大成功，主要得益于查询优化技术的发展。对于一个复杂的查询，寻找一个优化的执行策略是数据库系统开发成功的关键所在，此项研究目前在数据库领域仍属于NP问题。在查询执行的过程中，低效的SQL查询语句,概貌信息的匮乏、连接顺序的错误选择都是直接导致查询低效的原因

7、。【关键词】：数据库技术；查询优化技术；SQL语言；低效1外文摘要QueryTechnologyofDatabaseSystemsStudent:MathematicsTutor:Mathematics【Summary】Databasetechnologyisthebasictheoryandimplementationmethodsthroughresearchdatabasestructure,storage,design,management,andapplication,andusethesetheoriestoachievet

8、hedatainthedatabaseforprocessing,analysisandunderstandingofthetechnology.Namely:databasetechnologyisaso