MySQL 只能有一个自动列
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There can be only one auto column
提问by BuddyJoe
How do I correct the error from MySQL 'you can only have one auto increment column'.
如何更正 MySQL 中的错误“您只能有一个自动增量列”。
CREATE TABLE book (
id INT AUTO_INCREMENT NOT NULL,
accepted_terms BIT(1) NOT NULL,
accepted_privacy BIT(1) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
回答by emstol
My MySQL says "Incorrect table definition; there can be only one auto column and it must be defined as a key" So when I added primary key as below it started working:
我的 MySQL 说“不正确的表定义；只能有一个自动列，它必须被定义为一个键”所以当我添加如下主键时，它开始工作：
CREATE TABLE book (
id INT AUTO_INCREMENT NOT NULL,
accepted_terms BIT(1) NOT NULL,
accepted_privacy BIT(1) NOT NULL,
primary key (id)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
回答by TMS
The full error message sounds:
完整的错误消息听起来：
ERROR 1075 (42000): Incorrect table definition; there can be only one auto column and it must be defined as a key
ERROR 1075 (42000)：表定义不正确；只能有一个自动列，并且必须将其定义为键
So add primary keyto the auto_incrementfield:
所以添加primary key到auto_increment字段：
CREATE TABLE book (
id INT AUTO_INCREMENT primary key NOT NULL,
accepted_terms BIT(1) NOT NULL,
accepted_privacy BIT(1) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
回答by Matthew Read
Note also that "key" does not necessarily mean primarykey. Something like this will work:
另请注意，“键”不一定表示主键。像这样的事情会起作用：
CREATE TABLE book (
isbn BIGINT NOT NULL PRIMARY KEY,
id INT NOT NULL AUTO_INCREMENT,
accepted_terms BIT(1) NOT NULL,
accepted_privacy BIT(1) NOT NULL,
INDEX(id)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
This is a contrived example and probably not the best idea, but it can be very useful in certain cases.
这是一个人为的例子，可能不是最好的主意，但它在某些情况下非常有用。
回答by Deept Raghav
CREATE TABLE book (
id INT AUTO_INCREMENT primary key NOT NULL,
accepted_terms BIT(1) NOT NULL,
accepted_privacy BIT(1) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1
