Question

我的MySQL上有五个表，都是InnoDB。

常规表

Table list
Table proc
Table views

联结表

Table l_p
Table l_p_views

CREATE TABLE IF NOT EXISTS `list` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  PRIMARY KEY (`id`),
) ENGINE=InnoDB  DEFAULT CHARSET=utf8 ;

CREATE TABLE IF NOT EXISTS `proc` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB  DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS `view` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
) ENGINE=InnoDB  DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS `l_proc` (
  `listId` int(10) unsigned NOT NULL,
  `procId` int(10) unsigned NOT NULL,
  PRIMARY KEY (`listId`,`procId`),
  KEY `l_process_ibfk_2` (`procId`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

ALTER TABLE `l_proc`
  ADD CONSTRAINT `l_proc_ibfk_1` FOREIGN KEY (`listId`) REFERENCES `list` (`id`)     ON     DELETE CASCADE ON UPDATE CASCADE,
  ADD CONSTRAINT `l_proc_ibfk_2` FOREIGN KEY (`procId`) REFERENCES `proc` (`id`) ON     DELETE CASCADE ON UPDATE CASCADE;

CREATE TABLE IF NOT EXISTS `l_p_view` (
  `listd` int(10) unsigned NOT NULL,
  `procId` int(10) unsigned NOT NULL,
  `viewId` int(10) unsigned NOT NULL,
  KEY `listId` (`listId`,`procId`,`viewId`),
  KEY `view` (`viewId`),
  KEY `l_p_view_ibfk_2_idx` (`procId`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

ALTER TABLE `l_p_view`
  ADD CONSTRAINT `l_p_view_ibfk_1` FOREIGN KEY (`listId`) REFERENCES `l_proc`     (`listId`) ON DELETE CASCADE ON UPDATE CASCADE,
  ADD CONSTRAINT `l_p_view_ibfk_3` FOREIGN KEY (`viewId`) REFERENCES `view` (`id`) ON     DELETE CASCADE ON UPDATE CASCADE,
  ADD CONSTRAINT `l_p_view_ibfk_4` FOREIGN KEY (`procId`) REFERENCES `l_proc`     (`procId`) ON DELETE CASCADE ON UPDATE CASCADE;

这个想法是，如果删除了列表记录，那么所有引用的l_proc和l_p_view记录也会被删除。这确实有效。

但是，当我使用listId和procId作为查询删除l_proc中的记录时，l_p_view中具有相同listId的所有记录都会立即被删除 - 它们的procId与提交的记录不同并不重要。 l_proc的原始删除查询。

我可以在这里找到什么？

RGDS， P上。

Answer 1

我会尝试替换它：

ALTER TABLE `l_p_view`
  ADD CONSTRAINT `l_p_view_ibfk_1` FOREIGN KEY (`listId`) REFERENCES `l_proc`     (`listId`) ON DELETE CASCADE ON UPDATE CASCADE,
  ADD CONSTRAINT `l_p_view_ibfk_3` FOREIGN KEY (`viewId`) REFERENCES `view` (`id`) ON     DELETE CASCADE ON UPDATE CASCADE,
  ADD CONSTRAINT `l_p_view_ibfk_4` FOREIGN KEY (`procId`) REFERENCES `l_proc`     (`procId`) ON DELETE CASCADE ON UPDATE CASCADE;

用这个：

ALTER TABLE `l_p_view`
  ADD CONSTRAINT `l_p_view_ibfk_1` FOREIGN KEY (`listId`,`procId`) REFERENCES `l_proc`     (`listId`,`procId`) ON DELETE CASCADE ON UPDATE CASCADE,
  ADD CONSTRAINT `l_p_view_ibfk_3` FOREIGN KEY (`viewId`) REFERENCES `view` (`id`) ON     DELETE CASCADE ON UPDATE CASCADE,

区别在于后者中有一个复合外键，意味着只有l_p_view中与list_id 和 proc_id匹配的l_proc行。 <{1}}表中已删除的行将被删除。

连接表上的MySQL外键问题

1 个答案: