MySQL不允许删除即使FK关系ON DELETE CASCADE设置

Question

我正在开发一个项目，该项目利用MySQL数据库来存储在多个网站上使用的代码片段。对于每个内容片段，我还会保留一个编辑历史记录表，每次更新代码段时都会向其添加记录。有时，最好完全删除一个片段，以及任何相关的编辑历史记录。设置数据库时，我将外键关系设置为ON DELETE CASCADE，以便删除该代码段将自动删除历史记录。但是，我收到以下错误：

  

查询错误：从SNIPPET删除，其中id = 1.无法删除或更新父行：外键约束失败（universal_content_repository/SNIPPET_EDIT_HISTORY，CONSTRAINT fk_SNIPPET_EDIT_HISTORYRelationship13 FOREIGN KEY（snippet_id）参考SNIPPET（id））

以下是我用来创建数据库的代码以及关系：

/*Schema universal_content_repository*/
CREATE SCHEMA IF NOT EXISTS `universal_content_repository`
DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci;

USE `universal_content_repository`;

CREATE TABLE `universal_content_repository`.`USER` (
`id` INT UNSIGNED NOT NULL AUTO_INCREMENT COMMENT 'Stores the ID for the User.',
`username` VARCHAR(20) NOT NULL, 
`first_name` VARCHAR(32) NOT NULL,
`last_name` VARCHAR(32) NOT NULL,
`is_active` VARCHAR(5) NOT NULL DEFAULT true,
`password` VARCHAR(32) NOT NULL,
`is_admin` BIT NOT NULL DEFAULT 0,
`prefers_wysiwyg` BIT DEFAULT 0,
PRIMARY KEY (`id`)
) COMMENT 'Stores information about all Users for the Universal Content Repository.' ENGINE=INNODB
ROW_FORMAT=DEFAULT;

CREATE TABLE `universal_content_repository`.`SNIPPET` (
`id` INT UNSIGNED NOT NULL AUTO_INCREMENT,
`title` VARCHAR(255) NOT NULL,
`content` TEXT NOT NULL,
`created_by` INT UNSIGNED,
`wysiwyg_editable` VARCHAR(6) NOT NULL DEFAULT true,
`is_enabled` BIT NOT NULL DEFAULT 1,
PRIMARY KEY (`id`)
) COMMENT 'Guarantees that no two snippets may have the same name or ID.' ENGINE=INNODB
ROW_FORMAT=DEFAULT;

CREATE TABLE `universal_content_repository`.`IMAGE` (
`id` INT UNSIGNED NOT NULL AUTO_INCREMENT,
`name` VARCHAR(32) NOT NULL,
`url` TEXT NOT NULL,
`alt` VARCHAR(32),
PRIMARY KEY (`id`)
) ENGINE=INNODB
ROW_FORMAT=DEFAULT;

CREATE TABLE `universal_content_repository`.`IMAGE_IN_SNIPPET` (
`rel_id` INT UNSIGNED NOT NULL AUTO_INCREMENT,
`snippet_id` INT UNSIGNED,
`image_id` INT UNSIGNED,
`position` INT COMMENT 'Stores the position of the image within the snippet, as notated in the snippet as [index]',
PRIMARY KEY (`rel_id`)
) ENGINE=INNODB
ROW_FORMAT=DEFAULT;

CREATE TABLE `universal_content_repository`.`SNIPPET_EDIT_HISTORY` (
`revision_id` INT UNSIGNED NOT NULL AUTO_INCREMENT,
`editing_user` INT UNSIGNED,
`snippet_id` INT UNSIGNED,
`old_contents` TEXT NOT NULL COMMENT 'Stores the old contents of the snippet.',
`edit_date` DATETIME NOT NULL COMMENT 'Stores the DateTime of the edit.',
PRIMARY KEY (`revision_id`)
) ENGINE=INNODB
ROW_FORMAT=DEFAULT;

CREATE TABLE `universal_content_repository`.`SESSION` (
`id` VARCHAR(32) NOT NULL COMMENT 'Stores the Session ID',
`access` INT(10) UNSIGNED NOT NULL,
`data` TEXT,
PRIMARY KEY (`id`)
) ENGINE=INNODB
ROW_FORMAT=DEFAULT;

ALTER TABLE `universal_content_repository`.`USER` ADD UNIQUE `Identifiers` (`id`,`username`);

ALTER TABLE `universal_content_repository`.`SNIPPET` ADD UNIQUE `identifiers` (`title`,`id`);

ALTER TABLE `universal_content_repository`.`SNIPPET` ADD CONSTRAINT `fk_SNIPPETRelationship8` FOREIGN KEY (`created_by`) REFERENCES `universal_content_repository`.`USER`(`id`) MATCH SIMPLE ON UPDATE RESTRICT ON DELETE RESTRICT;

ALTER TABLE `universal_content_repository`.`IMAGE_IN_SNIPPET` ADD CONSTRAINT `fk_IMAGE_IN_SNIPPETRelationship10` FOREIGN KEY (`snippet_id`) REFERENCES `universal_content_repository`.`SNIPPET`(`id`) MATCH SIMPLE ON UPDATE CASCADE ON DELETE CASCADE;

ALTER TABLE `universal_content_repository`.`IMAGE_IN_SNIPPET` ADD CONSTRAINT `fk_IMAGE_IN_SNIPPETRelationship11` FOREIGN KEY (`image_id`) REFERENCES `universal_content_repository`.`IMAGE`(`id`) MATCH SIMPLE ON UPDATE RESTRICT ON DELETE RESTRICT;

ALTER TABLE `universal_content_repository`.`SNIPPET_EDIT_HISTORY` ADD CONSTRAINT `fk_SNIPPET_EDIT_HISTORYRelationship12` FOREIGN KEY (`editing_user`) REFERENCES `universal_content_repository`.`USER`(`id`) MATCH SIMPLE ON UPDATE RESTRICT ON DELETE RESTRICT;

ALTER TABLE `universal_content_repository`.`SNIPPET_EDIT_HISTORY` ADD CONSTRAINT `fk_SNIPPET_EDIT_HISTORYRelationship13` FOREIGN KEY (`snippet_id`) REFERENCES `universal_content_repository`.`SNIPPET`(`id`) MATCH SIMPLE ON UPDATE CASCADE ON DELETE CASCADE;

如果您想查看数据库的图形表示，可以在SchemaBank查看。 对于没有SchemaBank帐户的人，这里是ER：

有什么想法吗？

Answer 1

看起来你的代码是对的。

如果可行，请转储该数据库并将其作为测试还原到其他服务器上。如果INNODB和MySQL内部状态不同步，那么应该在恢复到的服务器上为您提供性能良好的数据库。