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
- right balanced functor
- right balanced module
- right bimodule
- right bisector
- right brachiocephalic vein
- right bundle-branch block
- right cancellation
- right cancellation law
- right cancellative groupoid
- right cancellative semigroup
- right censored data
- right-censored data
- right chain ring
- right circular cone
- right circular cylinder
- right-circularly polarized light
- right closed martingale
- right coherent ring
- right comaximal elements
- right commom iliac vein
- right commutator
- right comodule
- right compatibility
- right compatible relation
- right complete category