[問題] SET NULL 問題

[herman602 (奸商)]

我使用的是MySQL InnoDB

目前有兩個資料表

announcement
+------------+--------------+------+-----+---------+----------------+
| Field      | Type         | Null | Key | Default | Extra          |
+------------+--------------+------+-----+---------+----------------+
| id         | int(11)      | NO   | PRI | NULL    | auto_increment |
| class      | int(11)      | YES  | MUL | NULL    |                |
| subject    | varchar(50)  | NO   |     | NULL    |                |
| content    | varchar(100) | NO   |     | NULL    |                |
| start_date | date         | NO   |     | NULL    |                |
| end_date   | date         | NO   |     | NULL    |                |
| contact_id | int(11)      | YES  | MUL | NULL    |                |
+------------+--------------+------+-----+---------+----------------+

announcement_class
+-------------+-------------+------+-----+---------+----------------+
| Field       | Type        | Null | Key | Default | Extra          |
+-------------+-------------+------+-----+---------+----------------+
| id          | int(11)     | NO   | PRI | NULL    | auto_increment |
| description | varchar(50) | NO   | UNI | NULL    |                |
+-------------+-------------+------+-----+---------+----------------+

CONSTRAINT `announcement_ibfk_4` FOREIGN KEY (`class`) REFERENCES
`announcement_class` (`id`) ON DELETE SET NULL ON UPDATE CASCADE,

CONSTRAINT `announcement_ibfk_3` FOREIGN KEY (`contact_id`) REFERENCES
`staff` (`id`) ON DELETE SET NULL ON UPDATE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=14 DEFAULT CHARSET=utf8


但是我這樣刪除nannouncement_class的時候

announcement裡面若有record參照到被刪除的nannouncement_class

理應上class要被設為NULL

但是我實際執行起來

那些有被參照到的record也被一併連鎖刪除了

請問是什麼問題呢?

謝謝!

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推 TeemingVoid:我遇過類似的的怪問題，請先執行:
→ TeemingVoid:show create table announcement_class;
→ TeemingVoid:看看有沒有針對同一欄位重複設定了foreign key。
您好

出現了這些...

| announcement_class | CREATE TABLE `announcement_class` (
  `id` int(11) NOT NULL auto_increment,
  `description` varchar(50) NOT NULL,
  PRIMARY KEY  (`id`),
  UNIQUE KEY `description` (`description`)
) ENGINE=InnoDB AUTO_INCREMENT=8 DEFAULT CHARSET=utf8 |
※ 編輯: herman602       來自: 219.68.58.62         (08/05 01:22)

已解決

肇因於前端SQL statement的問題...

導致讓我覺得被刪除了@@!

謝謝TeemingVoid大大~~~~!!
※ 編輯: herman602       來自: 219.68.58.62         (08/05 02:02)
推 TeemingVoid:兩三回合水球就發現問題點, 原PO絕頂聰明反應真快! ^^