全序时态模块模式的TO_TSNF分解问题研究

Research on TO_TSNF Decomposition with Total Order Temporal Module Scheme

在许多时态数据库应用中,都存在着涉及多时间粒度的约束。但是,具有多时间粒度的时态数据库的设计相当复杂,甚至难以实现,而现实世界中的许多应用所涉及到的时态类型集都能满足全序关系。同时,具有全序时态类型集的全序时态模块模式有着良好的特性,因此本文提出了全序时态模块模式、时刻关系模式、全序时态模块投影、全序时态简单候选关键字、全序时态三范式(TO_T3NF)和全序时态简单范式(TO_TSNF)等概念,并给出了全序时态简单范式的分解算法,对其正确性进行了证明,并对时间复杂度进行了分析。

Constraints involving multiple time granularities exist in many temporal database applications. However, design of temporal database with multiple time granularities is fairly complicated, even hard to implement. Temporal type sets involved in many real world applications can constitute one total order of types, and total order temporal module schemes with total order temporal type sets have fine properties. The concepts of total order temporal module scheme, tickwise relation scheme, total order temporal module projection, total order temporal simple candidate key, total order temporal 3NF and total order temporal SNF etc. are given in this paper. The total order temporal SNF decomposition algorithm, the proof for its correction and the time complexity analysis are also given in this paper.