摘要
本文讨论了关系数据库中实际数据依赖和用于规范化的函数依赖集之间的差异及过度规范化问题。研究了函数依赖集的闭包及Boyce-Codd范式的判定问题。提出了原子函数依赖集的概念,以此取代函数依赖集的闭包进行关系模式的规范化。并定义了一类对某NP-完全问题可解的实际问题。
This paper discusses the functional dependences of a relational schema and the overnormalization The closure of functional dependence's set and the decission of Boyce-Codd normal form are studied Atomic functional dependence and a class of relational schema which has feasible argrithm for it's NP-complete problem are defined.
出处
《新疆大学学报（自然科学版）》
CAS
1991年第2期38-41,共4页
Journal of Xinjiang University(Natural Science Edition)
关键词
关系模式
规范化
关系数据库
闭包
relational database
normalization
closure
functional dependence
Boyce-Codd normal form
