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
- culture medium
- culture medium of biohydrometallurgy microorganisms
- culture method for hookworm larvae
- culture modelling
- Culture Monthly
- culture nexus of power
- culture of Anthocidaris crassispina
- culture of Apostichopus japonicus
- culture of Artemia
- culture of black carp
- culture of black grunt，culture of Hapalogenys nitens
- culture of Boleophthalmus pectinirostris
- culture of Chanos chanos
- culture of Chelon haematocheilus
- culture of Chlamys farreri
- culture of Chromileptes altivelis
- culture of chrysanthemum in Tianjin
- culture of clamworm
- culture of conch
- culture of crab
- culture of Crassostrea gigas
- culture of Crassostrea gigas angulata
- culture of Cyclina sinensis
- culture of echinoderm
- culture of echiuroid worm