mysql三种提交类型

mysql提交分显式提交、隐式提交及自动提交。

(1) 显式提交
用COMMIT命令直接完成的提交为显式提交。其格式为：
SQL>COMMIT；

(2) 隐式提交
用SQL命令间接完成的提交为隐式提交。这些命令是：
ALTER，AUDIT，COMMENT，CONNECT，CREATE，DISCONNECT，DROP，
EXIT，GRANT，NOAUDIT，QUIT，REVOKE，RENAME。

(3) 自动提交
若把AUTOCOMMIT设置为ON，则在插入、修改、删除语句执行后，
系统将自动进行提交，这就是自动提交。其格式为：
SQL>SET AUTOCOMMIT ON；

隐式提交应用举例如下：

#表结构
mysql> show create table planet_user_blacklist\G;
*************************** 1. row ***************************
       Table: planet_user_blacklist
Create Table: CREATE TABLE `planet_user_blacklist` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `uid` int(11) unsigned NOT NULL DEFAULT '0' COMMENT '用户id',
  `created_at` int(11) unsigned NOT NULL DEFAULT '0' COMMENT '创建时间',
  `updated_at` int(11) unsigned NOT NULL DEFAULT '0' COMMENT '更新时间',
  `add_type` tinyint(1) unsigned DEFAULT '0' COMMENT '0系统添加,1手动录入',
  PRIMARY KEY (`id`),
  UNIQUE KEY `uq_uid` (`uid`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8mb4 COMMENT='用户黑名单'
1 row in set (0.00 sec)

#自动提交已被关闭
mysql> show variables like 'autocommit';;
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| autocommit    | OFF   |
+---------------+-------+
1 row in set (0.00 sec)

ERROR:
No query specified

#测试开始
mysql> select * from planet_user_blacklist;
+----+----------+------------+------------+------------+
| id | uid      | created_at | updated_at | add_type |
+----+----------+------------+------------+-----------+
|  1 | 29904034 |          1 |          2 |        0  |
|  2 |  2839939 |          2 |          2 |        0  |
+----+----------+------------+------------+----------+
2 rows in set (0.00 sec)

#开启事务
mysql> begin;
Query OK, 0 rows affected (0.00 sec)

#新增字段
mysql> alter table planet_user_blacklist add column address varchar(100) default '';
Query OK, 0 rows affected (0.08 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> update planet_user_blacklist set address = '广州市番禺区番禺广场' where id = 1;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> select * from planet_user_blacklist;
+----+----------+------------+------------+----------+--------------------------------+
| id | uid      | created_at | updated_at | add_type | address                        |
+----+----------+------------+------------+----------+--------------------------------+
|  1 | 29904034 |          1 |          2 |        0 | 广州市番禺区番禺广场           |
|  2 |  2839939 |          2 |          2 |        0 |                                |
+----+----------+------------+------------+----------+--------------------------------+
2 rows in set (0.00 sec)

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

#可见事物回滚新增字段仍然被保留
mysql> select * from planet_user_blacklist;
+----+----------+------------+------------+----------+---------+
| id | uid      | created_at | updated_at | add_type | address |
+----+----------+------------+------------+----------+---------+
|  1 | 29904034 |          1 |          2 |        0 |         |
|  2 |  2839939 |          2 |          2 |        0 |         |
+----+----------+------------+------------+----------+---------+
2 rows in set (0.00 sec)

mysql>