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。
数据库 数据库理论 释文 relational calculus 关系演算
- general source
- general space
- general specification for military aero-engines
- General's Residence in Yili
- general statement
- general static shift resistivity
- general strategy of national region development in China
- general stratigraphic column
- General Strike of Beijing-Hankou Railway Workers
- general structure of dictionary
- general structure on manifolds
- general structure theorem
- general structure theory
- general subsidies for purchasing agricultural supplies
- general sum
- general-sum game
- general supervision
- general surveillance circuit
- general survey of underground pipelines
- general survey prediction method
- Generals Yashu
- general syntactic processor
- general system
- general systems theory
- General System Theory