4.1 问题
本案例要求MySQL数据存储引擎的使用，完成以下任务操作：
查看服务支持的存储引擎
修改服务默认使用的存储引擎
查看表使用的存储引擎
设置表使用的存储引擎
修改表存储引擎
4.2 步骤
实现此案例需要按照如下步骤进行。
步骤一：查看服务支持的存储引擎
登入MySQL服务器，查看当前支持哪些存储引擎。
使用mysql命令连接，以root用户登入：
[root@dbsvr1 ~]# mysql -u root –p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 9
Server version: 5.7.17 MySQL Community Server (GPL)
Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql>
执行SHOW ENGINES\G指令可列表查看，MySQL 5.6可用的存储引擎有9种（除最后的FEDERATED以外，其他8种都支持），其中默认采用的存储引擎为InnoDB：
mysql> SHOW ENGINES\G
*************************** 1. row ***************************
Engine: InnoDB
Support: DEFAULT //此存储引擎为默认
Comment: Supports transactions, row-level locking, and foreign keys
Transactions: YES
XA: YES
Savepoints: YES
*************************** 2. row ***************************
Engine: MRG_MYISAM
Support: YES
Comment: Collection of identical MyISAM tables
Transactions: NO
XA: NO
Savepoints: NO
*************************** 3. row ***************************
Engine: MEMORY
Support: YES
Comment: Hash based, stored in memory, useful for temporary tables
Transactions: NO
XA: NO
Savepoints: NO
*************************** 4. row ***************************
Engine: BLACKHOLE
Support: YES
Comment: /dev/null storage engine (anything you write to it disappears)
Transactions: NO
XA: NO
Savepoints: NO
*************************** 5. row ***************************
Engine: MyISAM
Support: YES
Comment: MyISAM storage engine
Transactions: NO
XA: NO
Savepoints: NO
*************************** 6. row ***************************
Engine: CSV
Support: YES
Comment: CSV storage engine
Transactions: NO
XA: NO
Savepoints: NO
*************************** 7. row ***************************
Engine: ARCHIVE
Support: YES
Comment: Archive storage engine
Transactions: NO
XA: NO
Savepoints: NO
*************************** 8. row ***************************
Engine: PERFORMANCE_SCHEMA
Support: YES
Comment: Performance Schema
Transactions: NO
XA: NO
Savepoints: NO
*************************** 9. row ***************************
Engine: FEDERATED
Support: NO //此引擎不被支持
Comment: Federated MySQL storage engine
Transactions: NULL
XA: NULL
Savepoints: NULL
9 rows in set (0.01 sec)
步骤二：修改服务默认使用的存储引擎
在 mysql> 环境中，可以直接通过SET指令更改默认的存储引擎（只在本次连接会话过程中有效，退出重进即失效） 。比如临时修改为MyISAM，可执行下列操作：
mysql> SET default_storage_engine=MyISAM; //改用MyISAM引擎
Query OK, 0 rows affected (0.00 sec)
mysql> SHOW VARIABLES LIKE 'default_storage_engine'; //确认结果
+------------------------+--------+
| Variable_name | Value |
+------------------------+--------+
| default_storage_engine | MyISAM |
+------------------------+--------+
1 row in set (0.00 sec)
若希望直接修改MySQL服务程序所采用的默认存储引擎，应将相关设置写入配置文件/etc/my.cnf，并重启服务后生效。比如：
[root@dbsvr1 ~]# vim /etc/my.cnf
[mysqld]
.. ..
default_storage_engine=myisam //改用myisam引擎
[root@dbsvr1 ~]# systemctl restart mysqld.service //重启服务
重新登入 mysql> 确认修改结果：
[root@dbsvr1 ~]# mysql -u root -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 3
Server version: 5.7.17 MySQL Community Server (GPL)
Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> SHOW VARIABLES LIKE 'default_storage_engine';
+------------------------+--------+
| Variable_name | Value |
+------------------------+--------+
| default_storage_engine | MYISAM | //默认引擎已修改
+------------------------+--------+
1 row in set (0.00 sec)
mysql> exit
Bye
步骤三：查看表使用的存储引擎
登入MySQL服务器查看。
mysql> show create table user \G; //查看建表命令
*************************** 1. row ***************************
Table: user
Create Table: CREATE TABLE `user` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` char(50) DEFAULT NULL,
`age` tinyint(3) unsigned DEFAULT '19',
`password` char(1) DEFAULT NULL,
`uid` int(11) DEFAULT NULL,
`gid` int(11) DEFAULT NULL,
`comment` char(150) DEFAULT NULL,
`homedir` char(50) DEFAULT NULL,
`shell` char(50) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=46 DEFAULT CHARSET=latin1 //存储引擎是InnoDB
1 row in set (0.00 sec)
ERROR:
No query specified
mysql>
步骤四：设置表使用的存储引擎
登入MySQL服务器设置。
mysql> create table stuinfo( name char(10), age int )engine=memory;//设置
Query OK, 0 rows affected (0.12 sec)
mysql>
mysql> show create table stuinfo\G; //查看
*************************** 1. row ***************************
Table: stuinfo
Create Table: CREATE TABLE `stuinfo` (
`name` char(10) DEFAULT NULL,
`age` int(11) DEFAULT NULL
) ENGINE=MEMORY DEFAULT CHARSET=latin1 //存储引擎名
1 row in set (0.00 sec)
ERROR:
No query specified
mysql>
步骤五：修改表存储引擎
登入MySQL服务器修改。
mysql> alter table stuinfo engine=innodb; //修改
Query OK, 0 rows affected (0.54 sec)
Records: 0 Duplicates: 0 Warnings: 0
mysql>
mysql> show create table stuinfo\G; //查看
*************************** 1. row ***************************
Table: stuinfo
Create Table: CREATE TABLE `stuinfo` (
`name` char(10) DEFAULT NULL,
`age` int(11) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1 //当前存储引擎名
1 row in set (0.00 sec)
ERROR:
No query specified
mysql>
