如何选择我的主键？ [英] How to choose my primary key?

问题描述

我在选择主键找到了此阅读材料。

I found this reading material on choosing a primary key.

• 有关如何为给定表选择主键的指南/博客文章？


• 我应该使用自动递增/生成的键，还是应该将主键基于正在建模的数据（假设它具有真正唯一的字段）？


• 为了性能原因，主键永远长久，或者我可以将外部唯一ID作为主键，即使它是一个字符串吗？

推荐答案

我相信在实际使用自然键很少优于代理键。

I believe that in practice using a natural key is rarely better than a surrogate key.

以下是使用自然金钥作为主键的主要缺点：

The following are the main disadvantages of using a natural key as the primary key:

• 您可能键值不正确，或者您可能只想重命名键值。要编辑它，您必须更新所有使用它作为外键的表。

• You might have an incorrect key value, or you may simply want to rename a key value. To edit it, you would have to update all the tables that would be using it as a foreign key.

通常很难有一个真正的独特的自然关键字。

It is often difficult to have a truly unique natural key.

自然键通常是字符串。数字字段上的索引比字符串字段上的索引要紧凑得多。

Natural keys are often strings. An index on an numeric field will be much more compact than one on a string field.

主键的数据类型应该是什么。数字键通常表现更好，但你可以使用字符串，特别是如果表不大，引用它的表也不大。

There is no hard rule on what the data type of the primary key should be. A numeric key normally performs better, but you could use a string, especially if the table is not big, and the tables that reference it are not big either.

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