理学 数据库系统 释 relational calculus 关系演算 一种抽象的关系数据语言，它通过数理逻辑中的谓词演算表达查询的要求。
calculus of relations 关系演算
数据库 数据库理论 释文 relational calculus 关系演算
- sodium acetate
- sodium alginate
- sodium aluminate
- sodium aluminum hydride
- sodium and potassium metabolism
- sodium arsenite
- sodium arsenite; sodium metaarsenite
- sodium azide
- sodium benzoate
- sodium bicarbonate
- sodium bismuthate
- sodium borohydride
- sodium borosilicate glass
- sodium bromide
- sodium-calcium exchanger
- sodium carbonate
- sodium carbonate decahydrate
- sodium carbonate peroxide
- sodium carbonate sintering of rare earth concentrate
- sodium-carbon reactor
- sodium carboxymethyl cellulose
- sodium caseinate
- sodium channel
- sodium channel blockers
- sodium chlorate