关系演算 meaning in English

relation calculus
tuple relational calculus

First , in this paper , a paraconsistent relational data model and its algebraic operators are introduced briefly . then , paraconsistent relational calculus based on this model is discussed and domain relational calculus for paraconsistent database is presented
本文首先简要介绍了次协调关系数据模型及其代数运算,并在此基础上进一步讨论了次协调关系演算,提出了次协调关系上的域关系演算。