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
- pulse response
- pulse safety valve
- pulse sand fracturing
- pulse sequence
- pulse shape discrimination
- pulse-shape discrimination
- pulse shaping
- pulse signal
- pulse signal analyzer
- pulse signal generator
- pulse slope
- pulse smearing
- Pulse solid rocket motor
- pulse solution
- pulse soot blower
- pulse source
- pulse splitting
- pulse step
- pulse stop flow chromatography
- pulse stretcher
- pulse structure
- pulse system
- pulse technique
- pulse terahertz emitter
- pulse terahertz source based on super fast optoelectronic technology