SQL的查询速度优化方法  

Optimizing method for SQL query speed

作　　者：何满辉[1] 温廷新[1] 曲晓华[2] 

机构地区：[1]辽宁工程技术大学教务处,辽宁阜新123000 [2]辽宁大学外语学院,辽宁辽阳111000

出　　处：《辽宁工程技术大学学报（自然科学版）》2003年第2期246-248,共3页Journal of Liaoning Technical University (Natural Science)

摘　　要：数据库查询是关系数据模型中关系操作的重要组成部分,而查询速度的快慢是系统是否优化的一个重要指标,也是当前网 络数据库应用中所存在的瓶颈问题之一。本文从与数据库查询相关的索引、连接、Where子句等因素入手,结合实例分析了各因素对 查询速度的影响,总结出根据表的不同情况选择聚簇索引或非聚簇索引对查询速度有明显影响;在组合索引中,使用频率高的字段应 设置为前导列;建立充分的连接、优化Where子句对SQL的查询速度也有明显的提高。Database query is one important part of relation-operation in relation-data model, and fast or slow of query speed is one important index that shows if the system is optimizing, at present, which is also one bottle-neck question of query speed in the network-database application. The paper starts with the related factors about database query ,such as index, link, where-clause, and analyses the affection about query speed of these factors with examples, and concludes that choosing cluster or non-cluster according to deferent tables will effect query speed distinctly. In combinatorial index, the high-frequency field should be set as leading column; setting up full linkage,and optimizing where-clause will improve SQL query speed obviously .

关 键 词：数据库查询 关系数据模型 SQL 查询速度 优化方法 聚簇索引 连接 WHERE子句 组合索引 

分 类 号：TP311.13[自动化与计算机技术—计算机软件与理论]