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
- closing management for soil and water conservation
- closing overvoltage
- closing price
- closing process
- closing sum
- closing time
- closo
- closo-
- closo complex
- closo-complex
- closo metalloborane
- closo-metalloborane
- closo metallocarborane
- closo-metallocarborane
- clostridiosis
- Clostridium infection
- Clostridium thermocellum
- clostripain
- closure
- closure algebra
- closure amplitude
- closure axiom
- closure condition
- closure criterion
- closure density