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
- divisor of unity
- divisor of zero
- divisor problem
- divisor product
- divisor sum
- divisor sum function
- divisor theory
- Divorce
- divorce
- divorce by agreement in ancient China
- divorce digraph
- Divorce Italian Style
- Diwali
- diwa theory
- DiWei Kingdom
- diwuhui
- Diwu Lun
- dixanthogen
- Dixian
- Dixi opera
- Dixmier
- Dixmier mapping
- Dixon
- Dixon factorization method
- Dixon-Ferrar formula