MySQL错误在<column name>（检查数据类型）</column name>上创建外键

Question

我似乎无法在两张桌子之间设置Foreign Key。

以下是每个表的CREATE子句：

CREATE TABLE IF NOT EXISTS `dbname`.`CallRecord` (
  `id` INT NOT NULL AUTO_INCREMENT,
  `user_id` INT NOT NULL,
  `city_id` INT NOT NULL,
  `created` DATETIME NULL,
  `timestamp` TIMESTAMP NULL,
  PRIMARY KEY (`id`),
  INDEX `user_id_fk_idx` (`user_id` ASC),
  INDEX `city_id_fk_idx` (`city_id` ASC),
  CONSTRAINT `user_id_fk`
    FOREIGN KEY (`user_id`)
    REFERENCES `dbname`.`User` (`id`)
    ON DELETE RESTRICT
    ON UPDATE NO ACTION,
  CONSTRAINT `city_id_fk`
    FOREIGN KEY (`city_id`)
    REFERENCES `dbname`.`City` (`id`)
    ON DELETE RESTRICT
    ON UPDATE NO ACTION)
ENGINE = InnoDB;

这是另一张桌子：

CREATE TABLE IF NOT EXISTS `dbname`.`DataCallAssoc` (
  `id` INT NOT NULL AUTO_INCREMENT,
  `data_id` INT NOT NULL,
  `call_record_id` INT NOT NULL,
  PRIMARY KEY (`id`),
  INDEX `data_id_fk_idx` (`data_id` ASC),
  INDEX `call_record_id_fk_idx` (`call_record_id` ASC),
  CONSTRAINT `data_id_fk`
    FOREIGN KEY (`data_id`)
    REFERENCES `dbname`.`Data` (`id`)
    ON DELETE CASCADE
    ON UPDATE NO ACTION,
  CONSTRAINT `call_record_id_fk`
    FOREIGN KEY (`call_record_id`)
    REFERENCES `dbname`.`CallRecord` (`id`)
    ON DELETE CASCADE
    ON UPDATE NO ACTION)
ENGINE = InnoDB;

问题在于CONSTRAINT的最后DataCallAssoc：

  CONSTRAINT `call_record_id_fk`
    FOREIGN KEY (`call_record_id`)
    REFERENCES `dbname`.`CallRecord` (`id`)
    ON DELETE CASCADE
    ON UPDATE NO ACTION)

我收到此错误：

Error creating foreign key on call_record_id (check data types)

即使我单独创建表和外键。每个其他外键都可以工作，甚至其他指向CallRecord.id作为外键的表也可以工作。

我还检查了CallRecord.id在结构方面与DataCallAssoc.call_record_id相同。

Answer 1

如果在另一个表中已经有一个同名的外键，则会出现创建外键错误...（检查数据类型）错误。因此，如果您遇到这个最无用的错误消息，请确保您的数据类型匹配，并且外键名称是唯一的。希望这有助于某人。

Answer 2

除了确保数据类型相同外，对于某些类型（如bigint（20）），如果主键是无符号的，则外键也必须是无符号的。 ＆＃34;无符号＆＃34;是一个领域的属性之一。

Answer 3

我能够在localhost中重新创建表，我从第一个create删除了这个表，因为你没有显示USER或City表的结构，所以错误应该在那里

CONSTRAINT `user_id_fk`
    FOREIGN KEY (`user_id`)
    REFERENCES `dbname`.`User` (`id`)
    ON DELETE RESTRICT
    ON UPDATE NO ACTION,
  CONSTRAINT `city_id_fk`
    FOREIGN KEY (`city_id`)
    REFERENCES `dbname`.`City` (`id`)
    ON DELETE RESTRICT
    ON UPDATE NO ACTION) 

这就是我使用的原因。

CREATE TABLE IF NOT EXISTS `CallRecord` (
      `id` INT NOT NULL AUTO_INCREMENT,
      `user_id` INT NOT NULL,
      `city_id` INT NOT NULL,
      `created` DATETIME NULL,
      `timestamp` TIMESTAMP NULL,
      PRIMARY KEY (`id`),
      INDEX `user_id_fk_idx` (`user_id` ASC),
      INDEX `city_id_fk_idx` (`city_id` ASC)
    )
    ENGINE = InnoDB


    CREATE TABLE IF NOT EXISTS `DataCallAssoc` (
      `id` INT NOT NULL AUTO_INCREMENT,
      `data_id` INT NOT NULL,
      `call_record_id` INT NOT NULL,
      PRIMARY KEY (`id`),
      INDEX `data_id_fk_idx` (`data_id` ASC),
      INDEX `call_record_id_fk_idx` (`call_record_id` ASC),
        CONSTRAINT `call_record_id_fk`
        FOREIGN KEY (`call_record_id`)
        REFERENCES `CallRecord` (`id`)
        ON DELETE CASCADE
        ON UPDATE NO ACTION)
    ENGINE = InnoDB