强全序时态模式中混合依赖集成员籍问题的研究  

Study on Membership of Mixed Dependency Set in Strong Totally Ordered Temporal Scheme

作　　者：万静[1] 王晓宇[1] 郝忠孝[1,2] 

机构地区：[1]哈尔滨理工大学计算机科学与技术学院,哈尔滨150080 [2]哈尔滨工业大学计算机科学与技术学院,哈尔滨150001

出　　处：《计算机研究与发展》2009年第6期1028-1035,共8页Journal of Computer Research and Development

基　　金：黑龙江省自然科学基金项目(F200601)~~

摘　　要：对于TFD和RTMVD混合依赖集约束的强全序时态模式来说,成员籍问题的解决对设计有效的模式分解算法必不可少.由于强全序时态模式中多时间粒度的使用,使其成员籍问题的解决变得更加复杂.为此定义了强全序时态模式下的属性集在给定时态类型上的混合闭包、属性集的混合闭包、属性集在给定时态类型上的混合依赖基、属性集的混合依赖基等概念,给出了求强全序时态模式下属性集的混合闭包、属性集的混合依赖基以及TFD和RTMVD混合依赖集成员籍问题的算法,并对算法的可终止性、正确性进行了证明,对时间复杂性进行了分析.In temporal databases, besides the storage redundancy and update abnormity associated with temporal functional dependencies, there also exist those associated with temporal multi-valued dependencies. In the strong totally ordered temporal scheme with temporal functional dependencies and regular temporal multi-valued dependencies constraints, the solution of the membership problem is essential to design an effective scheme decomposition algorithm. However, in the strong totally ordered temporal scheme, the introduction of multiple time granularities makes it more difficult to solve the membership problem. The concepts of attribute sets＇ mixed closure on a certain temporal type, attribute sets＇ mixed closure, attribute sets＇ mixed dependency base on a certain temporal type and attribute sets＇ mixed dependency base in strong totally ordered temporal scheme are proposed. The algorithms of attribute sets＇ mixed closure, attribute sets＇ mixed dependency base and the membership problem of temporal functional dependencies and regular temporal multi-valued dependencies in strong totally ordered temporal scheme are proposed. The algorithms＇ termination and correction are proved and their complexities are discussed. These algorithms are the basis of further normalization of strong totally ordered temporal scheme.

关 键 词：多时间粒度 强全序时态模式 混合闭包 混合依赖基 成员籍 

分 类 号：TP311[自动化与计算机技术—计算机软件与理论]