mysql触发器小实验

use test; Database changed mysql> desc time; +-------+---------------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+---------------------+------+-----+---------+-------+ | id | bigint(60) unsigned | NO | | 0 | | +-------+---------------------+------+-----+---------+-------+ 1 row in set (0.01 sec) mysql> desc time_2; +-------+---------------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-------+---------------------+------+-----+---------+-------+ | id | bigint(60) unsigned | NO | | 0 | | +-------+---------------------+------+-----+---------+-------+ 1 row in set (0.01 sec) #创建触发器 当 time表插入一条的时候 time_2表也插入这条新增的数据 mysql> delimiter $$ mysql> create trigger t_afterinsert_on_time -> after insert on time for each row -> begin -> insert into time_2(id) values (new.id); -> end -> $$ Query OK, 0 rows affected (0.14 sec) mysql> insert into time values (100); -> $$ Query OK, 1 row affected (0.13 sec) mysql> select * from time;$$ +-----+ | id | +-----+ | 100 | +-----+ 1 row in set (0.00 sec) mysql> select * from time_2;$$ +-----+ | id | +-----+ | 100 | +-----+ 1 row in set (0.00 sec) mysql> show triggers;$$ +-----------------------+--------+-------+-----------------------------------------------------+--------+---------+----------+----------------+----------------------+----------------------+--------------------+ | Trigger | Event | Table | Statement | Timing | Created | sql_mode | Definer | character_set_client | collation_connection | Database Collation | +-----------------------+--------+-------+-----------------------------------------------------+--------+---------+----------+----------------+----------------------+----------------------+--------------------+ | t_afterinsert_on_time | INSERT | time | begin insert into time_2(id) values (new.id); end | AFTER | NULL | | root@localhost | gbk | gbk_chinese_ci | utf8_general_ci | +-----------------------+--------+-------+-----------------------------------------------------+--------+---------+----------+----------------+----------------------+----------------------+--------------------+ 1 row in set (0.01 sec) #创建触发器 当 time表删除一条的时候 time_2表也删除这条数据 mysql> create trigger t_afterdelete_on_time -> after delete on time for each row -> begin -> delete from time_2 where id=old.id; -> end -> $$ Query OK, 0 rows affected (0.14 sec) mysql> show triggers; -> $$ +-----------------------+--------+-------+-----------------------------------------------------+--------+---------+----------+----------------+----------------------+----------------------+--------------------+ | Trigger | Event | Table | Statement | Timing | Created | sql_mode | Definer | character_set_client | collation_connection | Database Collation | +-----------------------+--------+-------+-----------------------------------------------------+--------+---------+----------+----------------+----------------------+----------------------+--------------------+ | t_afterinsert_on_time | INSERT | time | begin insert into time_2(id) values (new.id); end | AFTER | NULL | | root@localhost | gbk | gbk_chinese_ci | utf8_general_ci | | t_afterdelete_on_time | DELETE | time | begin delete from time_2 where id=old.id; end | AFTER | NULL | | root@localhost | gbk | gbk_chinese_ci | utf8_general_ci | +-----------------------+--------+-------+-----------------------------------------------------+--------+---------+----------+----------------+----------------------+----------------------+--------------------+ 2 rows in set (0.01 sec) mysql> delete from time where id=100;$$ Query OK, 1 row affected (0.09 sec) mysql> select * from time;$$ Empty set (0.00 sec) mysql> select * from time_2;$$ Empty set (0.00 sec) mysql> exit

 

mysql触发器小实验

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