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
- lacunary
- lacunary end
- lacunary Fourier series
- lacunary function
- lacunary interpolation
- lacunary inversion theorem
- lacunary power series
- lacunary principle
- lacunary sequence
- lacunary series
- lacunary space
- lacunary system of functions
- lacunary trigonometric series
- lacuna vasorum
- lacus
- Lacus Aestatis
- Lacus Autumni
- Lacus Bonitatis
- Lacus Doloris
- Lacus Excellentiae
- Lacus Felicitatis
- Lacus Gaudii
- Lacus Hiemalis
- Lacus Lenitatis
- Lacus Luxuriae