The foundation of relational database design--paradigm

First normal: There are no duplicate columns.

Second paradigm: To have a unique identity.

The third paradigm: not dependent on non-primary keys.

Implemented the third paradigm, which shows that the first and second paradigm have been realized.

does not conform to the third paradigm, the database table will have a pruning exception, and generate a large amount of redundant data.

For a better understanding of the meaning of the three paradigms, please refer to: http://baike.baidu.com/view/26218.htm

The foundation of relational database design--paradigm