mysql触发器
来源:互联网 发布:家电2017销售数据 编辑:程序博客网 时间:2024/09/21 08:17
触发器,一般不要单独调用,主要发生响应的事件mysql会自动调用。
语法:
create trigger 触发器名称 指定执行的时间 on 指定在什么表上执行操作 影响的行数 需要执行的任务或者业务
mysql> desc data
-> ;
+-------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| name | varchar(20) | YES | | NULL | |
+-------+-------------+------+-----+---------+-------+
1 row in set (0.01 sec)
mysql> desc chars;
+-------+---------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+---------+------+-----+---------+-------+
| count | int(10) | YES | | NULL | |
+-------+---------+------+-----+---------+-------+
1 row in set (0.01 sec)
mysql> insert into chars values(0);
Query OK, 1 row affected (0.05 sec)
mysql> create trigger tr1 after insert on data
-> for each row update chars set count=count+char_length(new.name);
Query OK, 0 rows affected (0.20 sec)
mysql> select * from chars;
+-------+
| count |
+-------+
| 0 |
+-------+
1 row in set (0.00 sec)
mysql> insert into data values("jack");
Query OK, 1 row affected (0.09 sec)
mysql> select * from chars;
+-------+
| count |
+-------+
| 4 |
+-------+
1 row in set (0.00 sec)
mysql> insert into data values("cainiao");
Query OK, 1 row affected (0.05 sec)
mysql> select * from chars;
+-------+
| count |
+-------+
| 11 |
+-------+
1 row in set (0.00 sec)
语法:
create trigger 触发器名称 指定执行的时间 on 指定在什么表上执行操作 影响的行数 需要执行的任务或者业务
mysql> desc data
-> ;
+-------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+-------+
| name | varchar(20) | YES | | NULL | |
+-------+-------------+------+-----+---------+-------+
1 row in set (0.01 sec)
mysql> desc chars;
+-------+---------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+---------+------+-----+---------+-------+
| count | int(10) | YES | | NULL | |
+-------+---------+------+-----+---------+-------+
1 row in set (0.01 sec)
mysql> insert into chars values(0);
Query OK, 1 row affected (0.05 sec)
mysql> create trigger tr1 after insert on data
-> for each row update chars set count=count+char_length(new.name);
Query OK, 0 rows affected (0.20 sec)
mysql> select * from chars;
+-------+
| count |
+-------+
| 0 |
+-------+
1 row in set (0.00 sec)
mysql> insert into data values("jack");
Query OK, 1 row affected (0.09 sec)
mysql> select * from chars;
+-------+
| count |
+-------+
| 4 |
+-------+
1 row in set (0.00 sec)
mysql> insert into data values("cainiao");
Query OK, 1 row affected (0.05 sec)
mysql> select * from chars;
+-------+
| count |
+-------+
| 11 |
+-------+
1 row in set (0.00 sec)
0 0
- 【mysql 触发器】触发器使用
- MYSQL 触发器
- mysql 触发器
- Mysql 触发器
- mysql 触发器
- mysql触发器
- MYSQL 触发器
- MySQL触发器
- mysql 触发器
- mysql触发器
- MYSQL 触发器
- mysql 触发器
- mysql 触发器
- MySQL触发器
- MYSQL触发器
- mysql触发器
- mysql触发器
- mysql触发器
- 使用Spring的注解方式实现AOP
- Python学习笔记(六)—几个标准类型内建函数
- 开端,我的C旅程
- 设计模式 应用场景
- 挂载盘显示busy
- mysql触发器
- poj——2856——Y2K Accounting Bug
- 关于UIView的autoresizingMask属性
- APIO2010:巡逻 树中最长K条链
- 来认真的了
- pat 1017
- 八大排序算法
- 小球下落
- android中11个