1、一个简单的事务

• 开启事务：start transaction
• 回滚事务：rollback
• 提交事务：commit

mysql> start transaction;
Query OK, 0 rows affected (0.00 sec)


mysql> update user set fee = 1200 where id = 1;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0


mysql> select * from user;
+----+-----------+-----+----------------------------------+-----------------+---------+---------+-----+---------------------+
| id | user_name | sex | password                         | email           | address | fee     | age | create_at           |
+----+-----------+-----+----------------------------------+-----------------+---------+---------+-----+---------------------+
|  1 | sian      | 男  | e10adc3949ba59abbe56e057f20f883e | [email protected]  | NULL    | 1200.00 |  32 | 2019-04-23 14:45:36 |
|  2 | 余西安    | 男  | c4ca4238a0b923820dcc509a6f75849b | [email protected]  | NULL    |    1.00 |  33 | 2019-04-21 17:12:55 |
|  3 | Jack      | 男  | c81e728d9d4c2f636f067f89cc14862c | [email protected] | NULL    |    0.00 |  22 | 2019-04-21 20:11:59 |
|  4 | Rose      | 女  | eccbc87e4b5ce2fe28308fd9f2a7baf3 | [email protected] | NULL    |    0.00 |  18 | 2019-04-22 10:46:41 |
|  5 | Sim       | 女  | a87ff679a2f3e71d9181a67b7542122c | [email protected]  | NULL    |    0.00 |  28 | 2019-04-22 10:46:41 |
|  6 | Tony      | 男  | c4ca4238a0b923820dcc509a6f75849b | [email protected] | NULL    |    0.00 |  22 | 2019-04-21 20:41:26 |
+----+-----------+-----+----------------------------------+-----------------+---------+---------+-----+---------------------+
6 rows in set (0.00 sec)


mysql> rollback;
Query OK, 0 rows affected (0.00 sec)


mysql> select * from user;
+----+-----------+-----+----------------------------------+-----------------+---------+---------+-----+---------------------+
| id | user_name | sex | password                         | email           | address | fee     | age | create_at           |
+----+-----------+-----+----------------------------------+-----------------+---------+---------+-----+---------------------+
|  1 | sian      | 男  | e10adc3949ba59abbe56e057f20f883e | [email protected]  | NULL    | 1100.00 |  32 | 2019-04-23 14:38:53 |
|  2 | 余西安    | 男  | c4ca4238a0b923820dcc509a6f75849b | [email protected]  | NULL    |    1.00 |  33 | 2019-04-21 17:12:55 |
|  3 | Jack      | 男  | c81e728d9d4c2f636f067f89cc14862c | [email protected] | NULL    |    0.00 |  22 | 2019-04-21 20:11:59 |
|  4 | Rose      | 女  | eccbc87e4b5ce2fe28308fd9f2a7baf3 | [email protected] | NULL    |    0.00 |  18 | 2019-04-22 10:46:41 |
|  5 | Sim       | 女  | a87ff679a2f3e71d9181a67b7542122c | [email protected]  | NULL    |    0.00 |  28 | 2019-04-22 10:46:41 |
|  6 | Tony      | 男  | c4ca4238a0b923820dcc509a6f75849b | [email protected] | NULL    |    0.00 |  22 | 2019-04-21 20:41:26 |
+----+-----------+-----+----------------------------------+-----------------+---------+---------+-----+---------------------+
6 rows in set (0.00 sec)

2、自动提交设置

• 默认情况下，每次执行sql语句都会自动提交(commit)；
• 查看当前自动提交状态：show variables like ‘%autocommit%’或select @@global.autocommit

mysql> show variables like '%autocommit%';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| autocommit    | ON    |
+---------------+-------+
1 row in set (0.00 sec)


mysql> set autocommit = off;
Query OK, 0 rows affected (0.00 sec)


mysql> show variables like '%autocommit%';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| autocommit    | OFF   |
+---------------+-------+
1 row in set (0.00 sec)