【摘要】 本文以空值的完全语义为基础，论述了在关系数据库中引入五值逻辑的必要性及可行性，给出了基于五值逻辑的关系数据库中算术运算及逻辑运算的运算规则。更多还原

【Abstract】 In this paper, 5 valued logic is presented Into relational database containing null value on the basis of complete semantics of null value. The feasibility and necessity of using 5 valUed logic are expended’ Comparative calculation and logical calculation undet 5 valued logic are defined at the end of the paper.更多还原