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
- clock cycle, clock period, clock tick
- clock dial
- clock distribution
- clock domain
- clock drift
- clock drive
- clock driver
- clock ensemble
- clock error
- clock gating
- clock generator
- clock hand
- clock indication
- clocking effect
- clocklike
- clock machine
- clock malfunction
- clock mechanism
- clock paradox
- clock period
- clock prime
- clock pulse
- clock-pulse generator
- clock rate
- clock reaction