Executing SQL script in server ERROR: Error 1005: Can't create table (errno: 150)

Question

What could be the reason for this error?

 CREATE  TABLE IF NOT EXISTS `myhotel`.`roomer` (
      `id` INT NOT NULL ,
      `name` VARCHAR(45) NOT NULL ,
      `start` DATE NOT NULL ,
      `finish` DATE NOT NULL ,
      `day` INT NOT NULL ,
      PRIMARY KEY (`id`) ,
      INDEX `fk_id` (`id` ASC) ,
      CONSTRAINT `fk_id`
        FOREIGN KEY (`id` )
        REFERENCES `myhotel`.`all_roomers` (`id_roomer` )
        ON DELETE NO ACTION
        ON UPDATE NO ACTION)
    ENGINE = InnoDB;

CREATE  TABLE IF NOT EXISTS `myhotel`.`all_roomers` (
  `id_roomer` INT NOT NULL ,
  `id_room` INT NOT NULL ,
  `status` TINYINT(1) NOT NULL ,
  INDEX `fk_id_room` (`id_room` ASC) ,
  PRIMARY KEY (`id_roomer`, `id_room`) ,
  CONSTRAINT `fk_id_room`
    FOREIGN KEY (`id_room` )
    REFERENCES `myhotel`.`room` (`id` )
    ON DELETE NO ACTION
    ON UPDATE NO ACTION)
ENGINE = InnoDB;

CREATE  TABLE IF NOT EXISTS `myhotel`.`room` (
  `id` INT NOT NULL AUTO_INCREMENT ,
  `number` INT NOT NULL ,
  `price` INT NOT NULL ,
  `capacity` INT NOT NULL ,
  `stars` INT NOT NULL ,
  `status` TINYINT(1) NOT NULL ,
  PRIMARY KEY (`id`) )
ENGINE = InnoDB;

The Error I get is : Executing SQL script in server

ERROR: Error 1005: Can't create table 'myhotel.roomer' (errno: 150)

Answer 1

According to the MySQL Docs (see here):

If MySQL reports an error number 1005 from a CREATE TABLE statement, and the error message refers to error 150, table creation failed because a foreign key constraint was not correctly formed.

I'd say from the looks of your script that it may be because the CREATE TABLE statement you're using references the table myhotel.all_roomers before it's created. I'd bet you need to create that table first before creating a foreign key reference to it.

Also, I'm not sure but it also looks as if you're using the id column as both a primary key as well as a foriegn key. I'm not sure this is allowed either but can't find anywhere in the documentation that says it's incorrect.