MySQL即使FK关系ON DELETE CASCADE集也不允许删除集

Question

我正在研究一个项目，该项目利用MySQL数据库存储了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，每次更新片段时都会向其添加记录。偶尔会希望完全删除代码段和任何关联的编辑历史记录。设置数据库时，我将外键关系设置为ON DELETE CASCADE，以便删除片段将自动删除历史记录。不过，我收到以下错误：

Error in query: delete from SNIPPET where id = 1. Cannot delete or update a parent row: a foreign key constraint fails (universal_content_repository/SNIPPET_EDIT_HISTORY , CONSTRAINT fk_SNIPPET_EDIT_HISTORYRelationship13 FOREIGN KEY (snippet_id) REFERENCES SNIPPET (id))

下面是我用它来创建数据库以及关系代码：如果你想看到数据库的图形表示

/*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; 

，你可以在SchemaBank看到它。 对于那些没有SchemaBank帐户，这里是ER：

任何想法？

Answer 1

看起来你的代码是正确的。

如果可行，转储该数据库并将其恢复到另一台服务器上作为测试。如果INNODB和MySQL内部状态已经不同步，那么应该会为您恢复到的服务器提供一个行为良好的数据库。