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
- new product development management
- new production capacity
- new product sales
- new protein resources
- New Providence Island
- new psychoactive substances
- New Psychological Literature
- new public administration
- new public administration theory
- new public management theory
- new public management（NPM）paradigm
- new public service theory
- new realism novel
- new realist evaluation
- new received pronunciation in the Republic of China
- New Record of a Drunken Man's Talk
- New Records of Jade Illumination
- new regional division of labor
- new regionalism
- New Rhenish Newspaper
- New Rhenish Newspaper: Politico-economic Review
- New Rhetoric
- new rhetoric
- New Rome
- new rural community