mysql - 如何进行所有插入然后检查外键约束？ (SQL 事务因外键约束而失败)

Question

我有两个表:

每副牌组(卡牌)始终属于某个玩家(一名玩家可以拥有 1..* 副牌)。此外，每个玩家总是有一套(而且只有一套)活跃套牌。

我想添加一个新玩家，但如果我只执行 INSERT INTO Players(...) VALUES (...)，我将没有 active_deck_id code> 应插入此查询中。同样，如果我从 decks 开始，我就不会有 player_id。

这就是我决定使用事务(在过程中)的原因:

CREATE PROCEDURE `add_player` (IN login VARCHAR(255), IN password VARCHAR(255), 
    OUT player_id INT(11))
BEGIN
START TRANSACTION;
INSERT INTO `players` (id, `login`, `password`, registered, last_logged, active_deck_id) 
    VALUES ('', login, pass, now(), now(), 0);

SET player_id = LAST_INSERT_ID();
INSERT INTO `decks` (id, name, player_id) VALUES ('', `sample deck`, player_id);

COMMIT;
END
END

然后我刚刚调用它:

set @login = 'mylogin';
set @pass = 'pass';
call add_player(@login, @pass, @id);

...但我收到错误:

#1452 - Cannot add or update a child row: a foreign key constraint fails (`game`.`players`, CONSTRAINT `active_deck` FOREIGN KEY (`active_deck_id`) REFERENCES `decks` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION) 

那么，如何进行所有插入，然后检查外键约束？因为在第一次插入之后，约束应该被打破，但在整个事务之后，它们应该没问题。 p>

我的表的 SQL:

CREATE TABLE IF NOT EXISTS `game`.`decks` (
  `id` INT UNSIGNED NOT NULL AUTO_INCREMENT,
  `name` VARCHAR(255) NOT NULL,
  `player_id` INT UNSIGNED NOT NULL,
  PRIMARY KEY (`id`, `player_id`),
  INDEX `player` (`player_id` ASC),
  CONSTRAINT `player`
    FOREIGN KEY (`player_id`)
    REFERENCES `game`.`players` (`id`)
    ON DELETE NO ACTION
    ON UPDATE NO ACTION)
ENGINE = InnoDB;

CREATE TABLE IF NOT EXISTS `game`.`players` (
  `id` INT UNSIGNED NOT NULL AUTO_INCREMENT,
  `login` VARCHAR(255) NOT NULL,
  `password` VARCHAR(255) NOT NULL,
  `registered` DATETIME NOT NULL,
  `last_logged` DATETIME NOT NULL,
  `active_deck_id` INT UNSIGNED NOT NULL,
  PRIMARY KEY (`id`),
  INDEX `active_deck` (`active_deck_id` ASC),
  CONSTRAINT `active_deck`
    FOREIGN KEY (`active_deck_id`)
    REFERENCES `game`.`decks` (`id`)
    ON DELETE NO ACTION
    ON UPDATE NO ACTION)
ENGINE = InnoDB;

Answer 1

尝试这个命令

设置 FOREIGN_KEY_CHECKS = 0；

在进行插入之前，请将值设置为 1 将其打开。