我需要在MySQL中将不是主键的字段自动递增 [英] I need to auto_increment a field in MySQL that is not primary key

问题描述

现在，我有一个主键为auto_increment字段的表.但是，我需要将主键设置为username，date(以确保没有重复的用户名和日期).

Right now, I have a table whose primary key is an auto_increment field. However, I need to set the primary key as username, date (to ensure that there cannot be a duplicate username with a date).

但是，为了更改行信息(添加和删除)，我需要auto_increment字段.

I need the auto_increment field, however, in order to make changes to row information (adding and deleting).

在这种情况下通常会做什么?

What is normally done with this situation?

谢谢！

推荐答案

只需在(用户名，日期)的组合上设置唯一索引.

Just set a unique index on composite of (username, date).

ALTER TABLE `table` ADD UNIQUE INDEX `name` (`username`, `date`);

或者，您可以尝试

ALTER TABLE `table` DROP PRIMARY KEY, ADD PRIMARY KEY(`username`,`date`);

我认为在后一种情况下，您需要将这些列声明为NOT NULL.

and I think in the latter case you need those columns to be declared NOT NULL.

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