Question

我对MySQL关系有点麻烦。我想我的结构中缺少一些明显的东西。这是我的SQL：

DROP TABLE IF EXISTS `parentlist_comments`;
CREATE TABLE `parentlist_comments` (
  `id` char(36) NOT NULL,
  `parentlist_id` char(36) NOT NULL,
  `user_id` char(36) NOT NULL,
  `comment` char(50) NOT NULL,
  `accepted` tinyint(1) NOT NULL DEFAULT '0',
  `submitted` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`),
  KEY `fk_parentlist_comments_parentlist` (`parentlist_id`),
  KEY `fk_parentlist_comment_user` (`user_id`),
  CONSTRAINT `fk_parentlist_comments_parentlist` FOREIGN KEY (`parentlist_id`) REFERENCES `parentlists` (`id`) ON DELETE CASCADE ON UPDATE CASCADE,
  CONSTRAINT `fk_parentlist_comment_user` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

DROP TABLE IF EXISTS `parentlist_submissions`;
CREATE TABLE `parentlist_submissions` (
  `id` char(36) NOT NULL,
  `parentlist_id` char(36) NOT NULL,
  `type_id` char(36) NOT NULL,
  `name` char(25) NOT NULL,
  `user_id` char(36) NOT NULL,
  `accepted` tinyint(1) NOT NULL DEFAULT '0',
  `submitted` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `votes` int(3) NOT NULL DEFAULT '0',
  PRIMARY KEY (`id`),
  KEY `fk_parentlist_submissions_user` (`user_id`),
  KEY `fk_parentlist_submissions_list` (`parentlist_id`),
  KEY `fk_parentlist_submissions_type` (`type_id`),
  CONSTRAINT `fk_parentlist_submissions_list` FOREIGN KEY (`parentlist_id`) REFERENCES `parentlists` (`id`) ON DELETE CASCADE ON UPDATE CASCADE,
  CONSTRAINT `fk_parentlist_submissions_type` FOREIGN KEY (`type_id`) REFERENCES `types` (`id`) ON DELETE CASCADE ON UPDATE CASCADE,
  CONSTRAINT `fk_parentlist_submissions_user` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

DROP TABLE IF EXISTS `parentlists`;
CREATE TABLE `parentlists` (
  `id` char(36) NOT NULL,
  `name` char(20) NOT NULL,
  `description` char(50) NOT NULL,
  `user_id` char(36) NOT NULL,
  `max_comments` int(3) NOT NULL DEFAULT '0',
  `max_submissions` int(3) NOT NULL DEFAULT '10',
  `max_votes` int(3) NOT NULL DEFAULT '0',
  PRIMARY KEY (`id`),
  KEY `fk_list_user` (`user_id`),
  CONSTRAINT `fk_list_user` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8 ROW_FORMAT=FIXED;

DROP TABLE IF EXISTS `submissions`;
CREATE TABLE `submissions` (
  `id` char(36) NOT NULL,
  `type_id` char(36) NOT NULL,
  `name` char(30) NOT NULL,
  `description` char(50) NOT NULL,
  `embed` char(200) DEFAULT NULL,
  `user_id` char(36) NOT NULL,
  `accepted` tinyint(1) NOT NULL DEFAULT '0',
  `submitted` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  `votes` int(5) NOT NULL DEFAULT '0',
  PRIMARY KEY (`id`),
  KEY `fk_submission_user` (`user_id`),
  KEY `fk_submission_type` (`type_id`),
  CONSTRAINT `fk_submission_type` FOREIGN KEY (`type_id`) REFERENCES `types` (`id`) ON DELETE CASCADE ON UPDATE CASCADE,
  CONSTRAINT `fk_submission_user` FOREIGN KEY (`user_id`) REFERENCES `users` (`id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

DROP TABLE IF EXISTS `types`;
CREATE TABLE `types` (
  `id` char(36) NOT NULL,
  `name` char(20) NOT NULL,
  `description` char(20) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

DROP TABLE IF EXISTS `users`;
CREATE TABLE `users` (
  `id` char(36) NOT NULL,
  `name` char(20) NOT NULL,
  `password` char(20) NOT NULL,
  `email` char(50) NOT NULL,
  PRIMARY KEY (`id`)
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8;

我在parentlist_submissions中创建了一个名为submission_id的列。我正在尝试在parentlist_submissions.submission_id和submissions.id之间创建外键关系，当我尝试这样做时，我得到错误：Foriegn键约束失败。无论出于何种原因，我的查询浏览器都不允许我复制它。

非常感谢任何帮助！

Answer 1

该错误通常是由已经填充了违反约束的数据的表引起的。（请注意，如果您刚刚添加了列，则空值可能会出现问题。）

我猜，因为我没有看到您发布了创建submission_index列的语句或创建外键约束的位置。

Answer 2

您似乎缺少“parentlist_submissions.submission_id”列。

外键约束失败 - 可能误解了我的关系

2 个答案: