将带有FOREIGN KEY的表添加到MySQL数据库会导致errno 150 [英] Adding table with FOREIGN KEY to a MySQL database causes errno 150

问题描述

我正尝试执行以下SQL，并收到errno:150'无法创建表path_relations'作为响应.根据MySQL文档，这是由于我的FOREIGN KEY约束存在问题而引起的.我在做什么错了?

I'm attemping to execute the following SQL and am receiving errno: 150 'cannot create table path_relations' in response. According to the MySQL documentation this is caused by my FOREIGN KEY restraints having issues. What am I doing wrong?

DROP TABLE IF EXISTS `paths`;
DROP TABLE IF EXISTS `path_relations`;

CREATE TABLE `paths` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(256) CHARACTER SET utf8 DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=24 DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

CREATE TABLE `path_relations` (
    `ancestor` int(11) NOT NULL DEFAULT '0',
    `descendant` int(11) NOT NULL DEFAULT '0',
    PRIMARY KEY(`ancestor`, `descendant`),
    FOREIGN KEY(`ancestor`) REFERENCES paths(`id`),
    FOREIGN KEY(`descendant`) REFERENCES paths(`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

推荐答案

如果您使paths.id not 未签名，是否可以正常工作?

Does it work if you make paths.id not unsigned?

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