问题描述
这是一个常见的面试问题。我面对一次面试，面试官给了我一张桌子，问我告诉他桌子的正常形式是什么？如果它在## NF中，则将其归一化到下一个NF？
This is a common interview question. I faced one interview where the interviewer gave me one table and asked me tell him which normal form the table is in? If it's in ##NF, then normalize it to the next NF?
我总是对这些正常数据库形式感到困惑。
谁能向我解释这些正常形式，并举例说明如何将每个NF建模到表格中，以便对我的下一次面试有所帮助？
I'm always get confused between these normal forms of database.Can anyone explain to me these normal forms with a proper example of how each NF is modeled into table so it will help in my next interview?
推荐答案
Boyce Codd范式实际上是最重要的，也是最容易解释的：每个不重要的行列式都是一个超键（只要记住超键中的箭头）。较小的范式仅值得一提，因为在某些情况下BCNF不能保持依赖关系。
Boyce Codd Normal Form is really the most important and also the easiest to explain: Every non-trivial determinant is a superkey (just remember "arrows out of superkeys"). The lesser normal forms are only worth mentioning because BCNF is not dependency-preserving in a few cases.
休·达文（Hugh Darwen）的BCNF和5NF示例：
Examples of BCNF and 5NF by Hugh Darwen:
- Database Design Issues: Part I
- Database Design Issues: Part II
更多数学定义（Abiteboul等人）：
For more mathematical definitions (Abiteboul et al):
- Foundations of Databases: The Logical Level
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