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MySQL外键约束On Delete、On Update

时间：2021-07-01 10:21:17 帮助过：2人阅读

Table: CREATE TABLE `child` ( `par_id` int(11) NOT NULL, `child_id` int(11) NOT NULL, PRIMARY KEY (`par_id`,`child_id`), FOREIGN KEY (`par_id`) REFERENCES `parent` (`par_id`) ON DELETE CASCADE ON UPDATE CASCADE ) ENGINE=InnoDB DEFAULT CHARSET=utf8 Create Table: CREATE TABLE `parent` ( `par_id` int(11) NOT NULL, PRIMARY KEY (`par_id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8

使用mysql trigger实现
mysql> show   triggers\G$
*************************** 1. row ***************************
             Trigger: t12
               Event: UPDATE
               Table: t3
           Statement: begin
        update  t4 set  tid = new.id   where  tid = old.id;
        end
              Timing: AFTER
             Created: NULL
            sql_mode: NO_ENGINE_SUBSTITUTION
             Definer: root@localhost
character_set_client: gbk
collation_connection: gbk_chinese_ci
  Database Collation: utf8_general_ci
*************************** 2. row ***************************
             Trigger: t11
               Event: DELETE
               Table: t3
           Statement: begin
        update  t4 set  tid = 0     where  tid = old.id;
        end
              Timing: AFTER
             Created: NULL
            sql_mode: NO_ENGINE_SUBSTITUTION
             Definer: root@localhost
character_set_client: gbk
collation_connection: gbk_chinese_ci
  Database Collation: utf8_general_ci
2 rows in set (0.02 sec)

标签：innodb ble mode weight tab nbsp char trigger new

MySQL外键约束On Delete、On Update

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