摘要
通过对影响数据库SQL查询语句效率因素和DBMS优化器优化策略的分析，提出了避免使用不兼容数据类型、连接查询中应当多给连接条件提供冗余搜索参数、使用平均密度来估计命中记录数、避免WHERE子句中的条件参数使用其它数学操作符、避免使用 != 或<>等类的操作符、避免使用NOT EXISTS 和NOT IN等语句、聚簇函数使用应注意WHERE子句等SQL查询语句的基本优化方法。
By analyzing the optimization of DBMS and the factors that affect the SQL query efficiency, avoided non-compatible data model, supplied redundancy parameter to junction condition, estimated data logging with average density, avoided math command character such as ! = or < > in clause WHERE, and NOT EXISTS and NOT IN are introduced. The optimization methods of clause WHERE and SQL query sentence are considered at first when the functions are applied.
出处
《兵工自动化》
2001年第1期25-27,共3页
Ordnance Industry Automation
