无法在Mysql上创建表errno：150

Question

i get another errno 150 on mysql. i already look at table engine, column type, but no luck, its nothing wrong in my view.

where im going wrong this time?

i get error when creating tag table that relate to image_tag and tag_lang.

-- -----------------------------------------------------
-- Table `ratna`.`image_tag`
-- -----------------------------------------------------
DROP TABLE IF EXISTS `ratna`.`image_tag` ;

CREATE  TABLE IF NOT EXISTS `ratna`.`image_tag` (
  `id` INT(11) NOT NULL ,
  `tag` INT(11) NOT NULL ,
  PRIMARY KEY (`id`, `tag`) ,
  INDEX `image_fk` (`id` ASC) ,
  CONSTRAINT `image_fk`
    FOREIGN KEY (`id` )
    REFERENCES `ratna`.`image` (`id` )
    ON DELETE CASCADE
    ON UPDATE CASCADE)
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8;


-- -----------------------------------------------------
-- Table `ratna`.`tag_lang`
-- -----------------------------------------------------
DROP TABLE IF EXISTS `ratna`.`tag_lang` ;

CREATE  TABLE IF NOT EXISTS `ratna`.`tag_lang` (
  `id` INT(11) NOT NULL ,
  `lang` INT(20) NOT NULL ,
  `tag_desc` VARCHAR(200) CHARACTER SET 'utf8' COLLATE 'utf8_unicode_ci' NOT NULL ,
  PRIMARY KEY (`id`, `lang`) )
ENGINE = InnoDB
DEFAULT CHARACTER SET = utf8
COLLATE = utf8_general_ci;


-- -----------------------------------------------------
-- Table `ratna`.`tag`
-- -----------------------------------------------------
DROP TABLE IF EXISTS `ratna`.`tag` ;

CREATE  TABLE IF NOT EXISTS `ratna`.`tag` (
  `id` INT(11) NOT NULL AUTO_INCREMENT ,
  `name` VARCHAR(50) CHARACTER SET 'utf8' COLLATE 'utf8_unicode_ci' NOT NULL ,
  `seq` INT(11) NOT NULL ,
  PRIMARY KEY (`id`) ,
  INDEX `image_tag_fk` (`id` ASC) ,
  INDEX `tag_lang` (`id` ASC) ,
  CONSTRAINT `image_tag_fk`
    FOREIGN KEY (`id` )
    REFERENCES `ratna`.`image_tag` (`tag` )
    ON DELETE CASCADE
    ON UPDATE CASCADE,
  CONSTRAINT `tag_lang`
    FOREIGN KEY (`id` )
    REFERENCES `ratna`.`tag_lang` (`id` )
    ON DELETE CASCADE
    ON UPDATE CASCADE)
ENGINE = InnoDB
AUTO_INCREMENT = 13
DEFAULT CHARACTER SET = utf8
COLLATE = utf8_general_ci;

Answer 1

This:

    REFERENCES `ratna`.`image_tag` (`tag` )

is not valid, because image_tag does not have any index that begins with tag. As explained in the documentation:

InnoDB permits a foreign key to reference any index column or group of columns. However, in the referenced table, there must be an index where the referenced columns are listed as the first columns in the same order.

("The referenced table" in this case is image_tag, and "the referenced columns" are just tag.)