对连接依赖关系的正确处理方法——对规范理论中连接依赖问题处理的异议

A CORRECT PROCESSING METHOD FOR JOIN DEPENDENCY: AN OBJECTION TO THE PROCESS OF JOIN DEPENDENCY IN RELATIONAL DATA NORMALIZATION THEORY

本文阐明关系数据规范理论中的连接依赖在设计数据库系统时并不少见。通过Ｅ—Ｒ图揭示了连接依赖的本质问题。对关系模式规范理论中用一组５ＮＦ来替代连接依赖关系以消除异常现象的结论提出异议，论述了处理连接依赖的办法以及相应的算法。

Join dependency in relational data theory is not seldom seen during database systems designing. The nature of the join dependency is exposed through an Entity-Relationship approach. An objection is raised in the present paper to the conclusion drawn by using a set of 5NFs to substitute for the join dependency in order to remove the anomalies in present relational data normalization theory. A method for processing join dependency and corresponding algorithm are expounded.