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
- Urhe Qu
- URI
- Uriankha's Three Garrisons
- uric acid
- uricase
- uridine
- uridine diphosphate
- uridine diphosphate glucose
- uridine diphosphate glucose (UDPG)
- uridine diphosphate sugar
- uridine diphosphate sugar (UDPsugar)
- uridine monophosphate
- uridine triphosphate
- uridylic acid
- Uriel Weinreich
- urinalyses analyzing system
- urinary concentrating mechanism
- urinary concentration
- urinary diluting mechanism
- urinary dilution
- urinary fistula
- urinary incontinence
- urinary irritation symptoms
- urinary organ
- urinarypathogenic Escherichia coli infection