博伊斯·科德范式（BCNF）

范式（BCNF）"/>

博伊斯·科德范式（BCNF）

Boyce-Codd Normal Form or BCNF is an extension to the third normal form, and is also known as 3.5 Normal Form.

Boyce-Codd范式或BCNF是第三范式的扩展，也称为3.5范式。

演示地址

Follow the video above for complete explanation of BCNF. Or, if you want, you can even skip the video and jump to the section below for the complete tutorial.

请按照上面的视频完整了解BCNF。 或者，如果您愿意，甚至可以跳过视频并跳至下面的部分，以获取完整的教程。

In our last tutorial, we learned about the third normal form and we also learned how to remove transitive dependency from a table, we suggest you to follow the last tutorial before this one.

在上一篇教程中，我们了解了第三种范式，并且还学习了如何从表中删除传递依赖关系 ，建议您在学习本教程之前阅读上一篇教程。

BCNF规则 (Rules for BCNF)

For a table to satisfy the Boyce-Codd Normal Form, it should satisfy the following two conditions:

为了使表满足Boyce-Codd范式，它应满足以下两个条件：

1. It should be in the Third Normal Form.

   它应该是第三范式 。

2. And, for any dependency A → B, A should be a super key.

   并且，对于任何依赖关系A→B，A应该是一个超级键 。

The second point sounds a bit tricky, right? In simple words, it means, that for a dependency A → B, A cannot be a non-p