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
- WIM
- Wiman
- Wiman theorem
- Wiman-Valiron method
- WiMAX
- Wimbledon Lawn Tennis Championship
- WIMP
- WIMPs
- WIMPs miracle
- WIMPs奇迹
- Wim Wenders
- winch
- Winchester
- Winchester disk drive
- Winchester Statute
- Winchester technology
- WIND
- Wind
- wind
- windage
- windage adjustment
- windage heating effect
- Wind and Rain on the Xiang River by Xia Chang
- Wind and Snow in the Wilds
- wind and solar complementary water lifting irrigation