全序时态模式下函数依赖集的成员籍问题研究

摘要

时态函数依赖(TFD)约束的全序时态模式下, 成员籍问题是设计有效模式分解算法的关键.定义了全序时态模式下全序时态函数依赖集有效闭包、属性集在给定时态类型上的闭包、属性集的闭包等概念,根据这些概念,结合全序时态模式自身的特点,提出求全序时态模式下属性集在给定时态类型上的闭包以及时态函数依赖(TFD)集成员籍问题的算法,证明了算法的可终止性和正确性,分析算法的时间复杂性,为时态函数依赖环境下全序时态模式的进一步规范化提供了理论基础.%The paper studies the membership problem of functional dependency sets in the totally-ordered temporal scheme because in the totally-ordered temporal scheme constrained with temporal functional dependencies (TFD), the membership problem is essential to design of effective scheme decomposition algorithms. This paper defines the concepts of totally-ordered temporal functional dependency sets valid closure , attribute sets closure on a certain temporal type and attribute sets closure in a totally-ordered temporal scheme, and based on the concepts, presents the algorithms for attribute sets closure on a certain temporal type and the membership problem of temporal functional dependencies ( TFD) in the totally-ordered temporal scheme. The algorithms termination and correction are proved and the algorithms complexities are analyzed. The study provides the theoretical basis for further standardizing the totally-ordered temporal scheme in temporal functional dependencies.