外键关系约束 - 级联更新还有外键的其他值

Question

初始状态

parents
id    parent_validity
1     1
2     1

children
id    parent_id    child_validity
1     1            1
2     1            1
3     2            1

更新后需要的状态

parents
id    parent_validity
1     0 (updated as 0)
2     1

children
id    parent_id    child_validity
1     1            0 (This val is expected as 0)
2     1            0 (This val is expected as 0)
3     2            1 (This val is expected as no change)

我得到了什么

children
id    parent_id    child_validity
1     1            0
2     1            0
3     2            0 (all values under this column became 0)

我想要的是，如果我在tableparents中更新一个parent_validity，那么在tablechildren中相关的child_validity应该是更新。 related 的意思是 ids.

的外键关系

我的结果是：table parents 中的任何有效性更改都会更改 table children 中的所有有效性。

我不想用 PHP 做我要求的事情。让 MySQL 处理。

我无法在网络上为我的请求获得正确的搜索词，因此我无法找到任何解决方案。你能帮帮我吗

感谢您的帮助。

注意：我认为我的 q 标题需要更新。（那是我最好的，抱歉。）

my sql 创建并给出约束

CREATE TABLE `parents` (
  `id` int(2) unsigned NOT NULL AUTO_INCREMENT,
  `parent_validity` bit(1) NOT NULL COMMENT '1:valid or 0:invalid',  
  PRIMARY KEY (`id`),
  KEY (`parent_validity`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

CREATE TABLE `children` (
  `id` int(2) unsigned NOT NULL AUTO_INCREMENT,
  `parent_id` int(2) unsigned NOT NULL,
  `child_validity` bit(1) NOT NULL COMMENT '1:valid or 0:invalid',  
  PRIMARY KEY (`id`),
  KEY (`child_validity`),
  CONSTRAINT fk_parent_id FOREIGN KEY (parent_id)  REFERENCES parents(id) ON UPDATE CASCADE,
  CONSTRAINT fk_parent_validity FOREIGN KEY (child_validity)  REFERENCES parents(parent_validity) ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;

Answer 1

正在创建约束 CONSTRAINT fk_parent_validity FOREIGN KEY (child_validity) REFERENCES parents(parent_validity) ON UPDATE CASCADE 在您的表之间创建一个新的外键。

当您使用值 1 更新 parent_validity 并将其更改为 0 时，MySQL 将其与外键级联以设置值为 1 的所有引用并更新为 0 (在这种情况下，所有 child_validity 原来是 1).

您需要使用更新触发器而不是外键。触发器是附加程序，当数据库上发生事件时，它会自动运行。这里需要一个 "UPDATE" 触发器。

认为这可能有效：

CREATE TRIGGER update_child_validitiy AFTER UPDATE ON parents FOR EACH ROW BEGIN UPDATE children SET child_validity = NEW.parent_validity WHERE id = NEW.id; END;

我没有经常使用触发器，但希望这些链接能有所帮助：

http://dev.mysql.com/doc/refman/5.7/en/trigger-syntax.html https://www.techonthenet.com/mysql/triggers/after_update.php

Answer 2

选项是复合键，但您应该评估这对您的解决方案的设计影响：

mysql> DROP TABLE IF EXISTS `children`, `parents`; 
Query OK, 0 rows affected (0.00 sec)

mysql> CREATE TABLE `parents` (
    ->   `id` int(2) unsigned NOT NULL AUTO_INCREMENT,
    ->   `parent_validity` bit(1) NOT NULL COMMENT '1:valid or 0:invalid',  
    ->   PRIMARY KEY (`id`, `parent_validity`)
    -> );
Query OK, 0 rows affected (0.00 sec)

mysql> CREATE TABLE `children` (
    ->   `id` int(2) unsigned NOT NULL AUTO_INCREMENT,
    ->   `parent_id` int(2) unsigned NOT NULL,
    ->   `child_validity` bit(1) NOT NULL COMMENT '1:valid or 0:invalid',  
    ->   PRIMARY KEY (`id`),
    ->   KEY (`parent_id`, `child_validity`),
    ->   CONSTRAINT `fk_parent_id_child_validity` FOREIGN KEY (`parent_id`, `child_validity`)
    ->   REFERENCES `parents` (`id`, `parent_validity`) ON UPDATE CASCADE
    -> );
Query OK, 0 rows affected (0.01 sec)

mysql> INSERT INTO
    ->   `parents`
    -> VALUES
    ->   (NULL, 1), (NULL, 1);
Query OK, 2 rows affected (0.00 sec)
Records: 2  Duplicates: 0  Warnings: 0

mysql> INSERT INTO
    ->   `children`
    -> VALUES
    ->   (NULL, 1, 1),
    ->   (NULL, 1, 1),
    ->   (NULL, 2, 1);
Query OK, 3 rows affected (0.00 sec)
Records: 3  Duplicates: 0  Warnings: 0

mysql> SELECT
    ->   `id`,
    ->   CONVERT(`parent_validity`, UNSIGNED) `parent_validity`
    -> FROM
    ->   `parents`;
+----+-----------------+
| id | parent_validity |
+----+-----------------+
|  1 |               1 |
|  2 |               1 |
+----+-----------------+
2 rows in set (0.00 sec)

mysql> SELECT
    ->   `id`,
    ->   `parent_id`,
    ->   CONVERT(`child_validity`, UNSIGNED) `child_validity`
    -> FROM
    ->   `children`;
+----+-----------+----------------+
| id | parent_id | child_validity |
+----+-----------+----------------+
|  1 |         1 |              1 |
|  2 |         1 |              1 |
|  3 |         2 |              1 |
+----+-----------+----------------+
3 rows in set (0.00 sec)

mysql> UPDATE `parents`
    -> SET `parent_validity` = 0
    -> WHERE `id` = 1;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> SELECT
    ->   `id`,
    ->   CONVERT(`parent_validity`, UNSIGNED) `parent_validity`
    -> FROM
    ->   `parents`;
+----+-----------------+
| id | parent_validity |
+----+-----------------+
|  1 |               0 |
|  2 |               1 |
+----+-----------------+
2 rows in set (0.00 sec)

mysql> SELECT
    ->   `id`,
    ->   `parent_id`,
    ->   CONVERT(`child_validity`, UNSIGNED) `child_validity`
    -> FROM
    ->   `children`;
+----+-----------+----------------+
| id | parent_id | child_validity |
+----+-----------+----------------+
|  1 |         1 |              0 |
|  2 |         1 |              0 |
|  3 |         2 |              1 |
+----+-----------+----------------+
3 rows in set (0.00 sec)

外键关系约束 - 级联更新还有外键的其他值

foreign key relation constraint - cascade on update also the other value of the foreign id

mysql

foreign-keys

constraints

foreign-key-relationship