Mysql笔记--常用命令

查看建表语句

show create table tableName;

eg:

mysql> show create table demo; +-------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table | +-------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| demo  | CREATE TABLE `demo` (
 `uid` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
 `uname` varchar(500) DEFAULT NULL,
 `email` varchar(500) DEFAULT NULL,
 `createTime` datetime DEFAULT NULL,
 PRIMARY KEY (`uid`)
) ENGINE=MyISAM AUTO_INCREMENT=2 DEFAULT CHARSET=utf8 | +-------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

可以看到该表使用的数据引擎事 MyISAM (该引擎不支持事务)

查看可使用的数据引擎

show engines;

eg:

mysql> show engines;
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
| Engine             | Support | Comment                                                        | Transactions | XA   | Savepoints |
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
| MyISAM             | YES     | MyISAM storage engine                                          | NO           | NO   | NO         |
| CSV                | YES     | CSV storage engine                                             | NO           | NO   | NO         |
| MRG_MYISAM         | YES     | Collection of identical MyISAM tables                          | NO           | NO   | NO         |
| BLACKHOLE          | YES     | /dev/null storage engine (anything you write to it disappears) | NO           | NO   | NO         |
| MEMORY             | YES     | Hash based, stored in memory, useful for temporary tables      | NO           | NO   | NO         |
| FEDERATED          | NO      | Federated MySQL storage engine                                 | NULL         | NULL | NULL       |
| ARCHIVE            | YES     | Archive storage engine                                         | NO           | NO   | NO         |
| PERFORMANCE_SCHEMA | YES     | Performance Schema                                             | NO           | NO   | NO         |
| InnoDB             | DEFAULT | Supports transactions, row-level locking, and foreign keys     | YES          | YES  | YES        |
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
9 rows in set (0.00 sec)

可以看到只有InnoDB引擎才支持事务

修改表的数据引擎

alter table tableName engine=innodb;

eg:

mysql> alter table demo engine=innodb;
Query OK, 1 row affected (0.58 sec)
Records: 1  Duplicates: 0  Warnings: 0

mysql> show create table demo; +-------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table | Create Table | +-------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| demo  | CREATE TABLE `demo` (
 `uid` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
 `uname` varchar(500) DEFAULT NULL,
 `email` varchar(500) DEFAULT NULL,
 `createTime` datetime DEFAULT NULL,
 PRIMARY KEY (`uid`)
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8 | +-------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

修改默认的存储引擎

修改my.cnf文件,在[mysqld]下加入:

default-storage-engine=INNODB

修改默认的字符集

修改my.cnf文件,在[mysqld]下加入:

# charset
default-character-set=utf8 default-collation=utf8_general_ci character-set-server=utf8 collation-server=utf8_general_ci init-connect='SET NAMES utf8'