mysql> show variables like 'autocommit';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| autocommit    | ON    |
+---------------+-------+
-- 關(guān)閉自動事務(wù)
set autocommit = off;

mysql> show variables like 'autocommit';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| autocommit    | OFF   |
+---------------+-------+

-- 客戶端A關(guān)閉自動事務(wù)后操作數(shù)據(jù)
mysql> select * from my_class;
+----+--------+
| id | name   |
+----+--------+
|  1 | 一班   |
|  3 | 三班   |
+----+--------+
2 rows in set (0.01 sec)
mysql> insert into my_class (name) values('四班');
Query OK, 1 row affected (0.00 sec)

mysql> select * from my_class;
+----+--------+
| id | name   |
+----+--------+
|  1 | 一班   |
|  3 | 三班   |
|  5 | 四班   |
+----+--------+
3 rows in set (0.00 sec)
-- 客戶端B看不到新增的 四班數(shù)據(jù), 
mysql> select * from my_class;
+----+--------+
| id | name   |
+----+--------+
|  1 | 一班   |
|  3 | 三班   |
+----+--------+
2 rows in set (0.00 sec)

-- 1、開啟事務(wù)，從這條語句開始，后面所有的語句都不會直接寫入到數(shù)據(jù)表，保存在事務(wù)日志中
start transaction 
-- 2、事務(wù)處理，多個指令構(gòu)成
-- 3、事務(wù)提交，結(jié)束事務(wù)
commit / rollback 

mysql> select * from my_class;
+----+--------+
| id | name   |
+----+--------+
|  1 | 一班   |
|  3 | 三班   |
|  5 | 四班   |
+----+--------+
3 rows in set (0.04 sec)
mysql> select * from my_student;
+----+--------+----------+------+--------+
| id | name   | class_id | age  | gender |
+----+--------+----------+------+--------+
|  1 | 劉備   |        1 |   18 |      2 |
|  2 | 李四   |        1 |   19 |      1 |
|  3 | 王五   |     NULL |   20 |      2 |
|  4 | 張飛   |     NULL |   21 |      1 |
|  5 | 關(guān)羽   |     NULL |   22 |      2 |
|  6 | 曹操   |        1 |   20 |   NULL |
+----+--------+----------+------+--------+
6 rows in set (0.00 sec)
-- 開啟事務(wù)
start transaction;
-- 執(zhí)行事務(wù)操作，多個修改操作
insert into my_class (name)values ('六班');
insert into my_student (name, class_id, age, gender)values ('司馬懿', 6, 26, 1);
-- 提交事務(wù)
commit;
-- 或者回滾操作，所有數(shù)據(jù)無效清空
rollback;

-- 增加回滾點
savepoint 回滾點名字;
-- 回到回滾點 清空之后所有操作
rollback to 回滾點名字;