理学 数据库系统 释 query optimization 查询优化 查询优化旨在通过选择有效策略，对给定的关系表达式求值，使得查询代价最小。
数据库 数据库管理系统及其实现技术 释文 query optimization 查询优化
- switched current
- switched Ethernet
- switched receiver
- switched rectifier circuit
- switched reluctance generator
- switched reluctance machine
- switched system
- switcher
- switch function
- switchgear
- switchgear arrangement
- switchgear cubicle
- switchgear cubicle for loop network
- switch gene
- switchgrass
- switch grinder car
- switchgroup
- switching
- switching circuit
- switching class
- switching diode
- switching field
- switching hub
- switching map
- switching model