MySQLの外部キー制約RESTRICT,CASCADE,SET NULL,NO ACTIONの違いは？ - Qiita

-- Create syntax for TABLE 'categories' CREATE TABLE `categories` ( `id` int(11) unsigned NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; -- Create syntax for TABLE 'items' CREATE TABLE `items` ( `id` int(11) unsigned NOT NULL, `category_id` int(11) unsigned NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8;

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外部キー制約の挙動