找到正确的主键

Question

我决定将三个值的组合设置为数据库表的主键（复合键），大多数情况下前两列是唯一的，但在某些情况下，第三列的值在同一时间都相同问题是第三列是描述，它是用户可以输入的任何字符串。我知道不建议用户给定字符串作为主键，但是可以吗？将其作为组合键的一部分。我真的没有其他选择。

Answer 1

If at all possible, you should add a surrogate primary key, meaning a key that is unique and has no business meaning whatsoever.

Composite primary keys very often turn out to be less 'stable' than anticipated - but if you MUST use one, using one or more component columns over which the user has little or no control (like created_timestamp) would be preferable.

Answer 2

Add a separate column called id and make it auto increment and use this column as a primary key .

Hope this will solve your problem.

Cheers.