理学 数据库系统 释 relational algebra 关系代数 一种抽象的关系数据语言，它通过对关系的运算来表达查询。
algebra of relations 关系代数 relation algebra 关系代数 relational algebra 关系代数 relationship algebra 关系代数
数据库 数据库理论 释文 relational algebra 关系代数
- extreme value memory method
- extreme-value problem
- extreme-value theorem
- extreme-value theory
- extreme weather and climate events
- extreme weather disaster map
- extreme yang changing into yin
- extreme yin changing into yang
- extremity
- extremization
- extremophile
- extremozymes
- extremum
- extremum condition
- extremum in the large
- extremum of a function
- extremum principle
- extremum problem
- extremum property
- extremum test
- extremum value
- extrication force
- extrinsic
- extrinsic absorption
- extrinsic allergic alveolitis