时态数据库初等关键字范式问题的研究

为了探索能避免存储异常(插入，删除，修改异常，冗余)，保证数据的完整性和一致性的数据库模式，依据具有多时间粒度的时态函数依赖约束的理论，采用时态数据库规范化方法，提出了时态初等关键字范式的概念，并分析了时态初等关键字范式与时态三范式和时态BC范式之间存在的联系，得到了用TEKNF分解来解决如果把TBCNF作为最终目标，很难实现保持函数依赖性，若把T3NF作为最终目标，又很难实现想要得到的规范化要求的问题，是时态数据库进一步规范化的基础．

Research on TEKNF in Temporal Database

In order to find a good database scheme which can avoid anomalies of operation (insertion, deletion, update anomalies,data redundancy) to preserve completion and consistency of the data. ,on the basis of the theory by using constraints of the temporal functional dependency with multiple temporal granularities, applying the method of temporal databbase normalization, this article presents the concept of TEKNF and analyses the relationship among the TEKNF,T3NF and TBCNF. For a temporal model with temporal multigranularities,it is difficult to depose it to TBCNF of keeping the temporal functional dependencies as well as to T3NF of satisfyinig the corresponding requirements of normal forms,so this article draws a conclusion of taking advantage of TEKNF. It is the foundation of the further normalization.