There can be only one auto column

How do I correct the error from MySQL 'you can only have one auto increment column'.

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;

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:

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;

The full error message sounds:

> ERROR 1075 (42000): Incorrect table definition; there can be only one auto column and it must be defined as a key

So add primary key to the auto_increment field:

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;

Note also that "key" does not necessarily mean primary key. Something like this will work:

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.

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

This happens with you because in the case that you didn't create a primary key, SEQUELIZE will automatically generate a primary key with a default name id. Which causes a duplication because you already created one and SEQUELIZE created one too. But when you defined id as a primary key. SEQUELIZE didn't create the default id primary key.