当我尝试插入一行时，它给了我错误代码：1452

Question

CREATE TABLE IF NOT EXISTS `game_review`.`comments` (
  `comment_id` INT NOT NULL AUTO_INCREMENT,
  `iduser` INT NOT NULL,
  `datePosted` DATETIME NOT NULL,
  `comments` LONGTEXT NOT NULL,
  `idgame` INT NOT NULL,
  PRIMARY KEY (`comment_id`),
  UNIQUE INDEX `comments_id_UNIQUE` (`comment_id`),
  INDEX `comment_user_id_idx` (`iduser`),
  INDEX `comment_game_id_idx` (`idgame`),
  CONSTRAINT `comment_user_id`
    FOREIGN KEY (`iduser`)
    REFERENCES `game_review`.`users` (`user_id`)
    ON DELETE CASCADE
    ON UPDATE NO ACTION,
  CONSTRAINT `comment_game_id`
    FOREIGN KEY (`idgame`)
    REFERENCES `game_review`.`games` (`game_id`)
    ON DELETE NO ACTION
    ON UPDATE NO ACTION)
ENGINE = InnoDB;


CREATE TABLE IF NOT EXISTS `game_review`.`users` (
  `user_id` INT NOT NULL AUTO_INCREMENT,
  `email_address` VARCHAR(45) NOT NULL,
  `password` VARCHAR(6) NOT NULL,
  `username` VARCHAR(20) NOT NULL,
  PRIMARY KEY (`user_id`),
  UNIQUE INDEX `user_id_UNIQUE` (`user_id`))
ENGINE = InnoDB;

这是动作：

INSERT INTO game_review.comments (iduser,datePosted,comments,idgame) VALUES(1,NOW(),"dsds",1)

这是回复：

错误代码：1452。无法添加或更新子行：外键约束失败 (game_review.comments, CONSTRAINT comment_game_id FOREIGN KEY (idgame) REFERENCES games (game_id) ON DELETE CASCADE ON UPDATE CASCADE)

Answer 1

您的games 表中没有存储 id 为 1 的游戏，这就是您收到错误的原因，因为 cmets 表有一个指向该表的 FK。