mysql 事务解析

drop table if exists t_user1;

create table t_user1(

id int(3) primary key auto_increment,

username varchar(10)

);

mysql> create table t_user1(

-> id int(3) primary key auto_increment,

-> username varchar(10)

-> );

Query OK, 0 rows affected (0.02 sec)

mysql> insert into t_user1(username) values('h1');

Query OK, 1 row affected (0.01 sec)

mysql> select * from t_user1;

+----+----------+

| id | username |

+----+----------+

| 1 | h1 |

+----+----------+

1 row in set (0.00 sec)

mysql> rollback;//回滚事务

Query OK, 0 rows affected (0.00 sec)

mysql> select * from t_user1;//回滚之后还是和之前一样，因为myql自动提交了

+----+----------+

| id | username |

+----+----------+

| 1 | h1 |

+----+----------+

1 row in set (0.00 sec)

mysql> start transaction;//手动开启事务，关闭事务自动提交

Query OK, 0 rows affected (0.00 sec)

mysql> insert into t_user1(username) values('h2');

Query OK, 1 row affected (0.01 sec)

mysql> insert into t_user1(username) values('h3');

Query OK, 1 row affected (0.00 sec)

mysql> insert into t_user1(username) values('h4');

Query OK, 1 row affected (0.00 sec)

mysql> select * from t_user1;

+----+----------+

| id | username |

+----+----------+

| 1 | h1 |

| 2 | h2 |

| 3 | h3 |

| 4 | h4 |

+----+----------+

4 rows in set (0.00 sec)

mysql> rollback;//回滚

Query OK, 0 rows affected (0.01 sec)

mysql> select * from t_user1;

+----+----------+

| id | username | 最后硬盘上的数据还是和之前一样。

+----+----------+ 回滚删除记录，不修改硬盘上的数据。

| 1 | h1 |

+----+----------+

1 row in set (0.00 sec)