基于特定关系模式下函数依赖集的闭包的研究

摘要

通过实例研究，定义了一个特定的关系模式，并称它为传递依赖关系模式．在传递依赖关系模式下，得出了计算函数依赖集的闭包中函数依赖的个数的公式，并依照具体实例设计了计算函数依赖集的闭包中所有函数依赖的算法，在此算法中，设计了多种计算属性集所有子集的算法．%This paper defines a specific relational schema that is called transitive dependency relational schema, according tostudying a case. Based on the transitive dependency relational schema, the paper proves a formula for computing the number of functional dependencies in the closure of functional dependency set and designs an algorithm for computing all functional dependencies in the closure of functional dependency set. In the algorithm, the paper also designs some algorithms for computing all subsets of attribute set.