关系数据规范理论第五范式的缺陷

Defect of Relational Data Normalization Theory 5NF

剖析了连接依赖的本质，并提出其产生的条件和处理的方法。指出连接依赖出现在联系关系中，且并不少见，但不能以一组5NF去替代原关系，否则会丢失信息，必须采用该文提出的方法去处理。

In this paper the nature of the join dependency is analyzed. and its causing conditions and processing method are presented. It showsthat the join dependency often appears in the relationship of entity-conjoin.However.the relationship cannot be replaced by a set of 5NF.The method presented in this paper must be used .otherwise the information will be lost .