【Mysql】修改mysql的字符集和默认存储引擎,解决数据入库乱码问题

背景

在使用Python + Testlink做自动化的过程中,遇到了数据入库出现乱码的情况,后来通过修改字符集的方式解决了这个问题。下面的内容主要来自于一篇相关博文,博主做了细微的调整,

原文链接:https://blog.csdn.net/wyzxg/article/details/7581415

【Mysql】修改mysql的字符集和默认存储引擎,解决数据入库乱码问题

Mysql的字符集分类

字符集类型 描述 对应系统变量
客户端字符集 通知server端,客户端提交的sql语句编码格式 character_set_client
连接字符集 server端翻译sql语句时,使用的编码格式 character_set_connectiont
结果集字符集 server端返回结果集之前把结果集转换成的编码格式 character_set_results
存储字符集 数据在存储引擎里编码格式 character_set_results/character_set_server

为了不出现乱码,我们需要统一修改这些参数,比如我要把数据库的默认字符集改为utf8,可以在[client]下添加如下参数 default-character-set=utf8,在[mysqld]下添加如下参数default-character-set=utf8,然后重启mysql服务,再查看字符集(要重新登录客户端)

查看Mysql库现有字符集

  • mysql> show variables like 'character%';
+--------------------------+--------------------------------+
| Variable_name | Value |
+--------------------------+--------------------------------+
| character_set_client | gbk |
| character_set_connection | gbk |
| character_set_database | latin1 |
| character_set_filesystem | binary |
| character_set_results | gbk |
| character_set_server | latin1 |
| character_set_system | utf8 |
| character_sets_dir | D:\xampp\mysql\share\charsets\ |
+--------------------------+--------------------------------+
8 rows in set (0.00 sec)
  • mysql> show variables like 'character%';
+--------------------------+--------------------------------+
| Variable_name | Value |
+--------------------------+--------------------------------+
| character_set_client | gbk |
| character_set_connection | gbk |
| character_set_database | latin1 |
| character_set_filesystem | binary |
| character_set_results | gbk |
| character_set_server | latin1 |
| character_set_system | utf8 |
| character_sets_dir | D:\xampp\mysql\share\charsets\ |
+--------------------------+--------------------------------+
8 rows in set (0.00 sec)
  • mysql> show variables like 'collation%';
+----------------------+-----------------+
| Variable_name | Value |
+----------------------+-----------------+
| collation_connection | utf8_general_ci |
| collation_database | utf8_general_ci |
| collation_server | utf8_general_ci |
+----------------------+-----------------+
3 rows in set (0.00 sec)

mysql的字符集分的比较细,可以采用默认值,也可以指定值

数据库字符集

创建使用默认字符集的库

  • mysql> create database db1;

    Query OK, 1 row affected (0.01 sec)
  • mysql> show create database db1;
+----------+--------------------------------------------------------------+
| Database | Create Database |
+----------+--------------------------------------------------------------+
| db1 | CREATE DATABASE `db1` /*!40100 DEFAULT CHARACTER SET utf8 */ |
+----------+--------------------------------------------------------------+
1 row in set (0.00 sec)

创建指定字符集的库

  • mysql> create database db2 default character set latin1;

    Query OK, 1 row affected (0.01 sec)

  • mysql> show create database db2;

+----------+----------------------------------------------------------------+
| Database | Create Database |
+----------+----------------------------------------------------------------+
| db2 | CREATE DATABASE `db2` /*!40100 DEFAULT CHARACTER SET latin1 */ |
+----------+----------------------------------------------------------------+
1 row in set (0.00 sec)

修改库的字符集

  • mysql> alter database db2 default character set utf8;

    Query OK, 1 row affected (0.00 sec)

  • mysql> show create database db2;

+----------+--------------------------------------------------------------+
| Database | Create Database |
+----------+--------------------------------------------------------------+
| db2 | CREATE DATABASE `db2` /*!40100 DEFAULT CHARACTER SET utf8 */ |
+----------+--------------------------------------------------------------+
1 row in set (0.00 sec)

表字符集

  • mysql> use db2;

    Database changed

创建使用默认库字符集的表

  • mysql> create table t1(a varchar(10));

    Query OK, 0 rows affected (0.01 sec)
  • mysql> show create table t1;
+-------+-------------------------------------------------------+
| Table | Create Table |
+-------+-------------------------------------------------------+
| t1 | CREATE TABLE `t1` (
`a` varchar(10) default NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8 |
+-------+-------------------------------------------------------+
1 row in set (0.00 sec)

创建指定字符集的表

  • mysql> create table t2(a varchar(10)) default character set latin1;;

    Query OK, 0 rows affected (0.01 sec)

    ERROR:

    No query specified

  • mysql> show create table t2;

+-------+-------------------------------------------------------+
| Table | Create Table |
+-------+-------------------------------------------------------+
| t2 | CREATE TABLE `t2` (
`a` varchar(10) default NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+-------+-------------------------------------------------------+
1 row in set (0.00 sec)

更改表的字符集

  • mysql> alter table t2 default character set utf8;

    Query OK, 0 rows affected (0.01 sec)

    Records: 0 Duplicates: 0 Warnings: 0

  • mysql> show create table t2;

+-------+--------------------------------------------------------+
| Table | Create Table |
+-------+--------------------------------------------------------+
| t2 | CREATE TABLE `t2` (
`a` varchar(10) character set latin1 default NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8 |
+-------+-------------------------------------------------------+
1 row in set (0.00 sec)

从上面可以看到,修改表的字符集时,不会影响已经存在列的字符集,但新增列将继承表的字符集,如下

  • mysql> alter table t2 add a2 varchar(10);

    Query OK, 0 rows affected (0.01 sec)

    Records: 0 Duplicates: 0 Warnings: 0

  • mysql> show create table t2;

+-------+---------------------------------------------+
| Table | Create Table |
+-------+---------------------------------------------+
| t2 | CREATE TABLE `t2` (
`a` varchar(10) character set latin1 default NULL,
`a2` varchar(10) default NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8 |
+-------+---------------------------------------------+
1 row in set (0.01 sec)

如果想更改已经存在表和字符列的字符集,要用如下方式

  • mysql> alter table t2 convert to character set latin1;

    Query OK, 0 rows affected (0.01 sec)

    Records: 0 Duplicates: 0 Warnings: 0

  • mysql> show create table t2;

+-------+--------------------------------------+
| Table | Create Table |
+-------+--------------------------------------+
| t2 | CREATE TABLE `t2` (
`a` varchar(10) default NULL,
`a2` varchar(10) default NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1 |
+-------+--------------------------------------+
1 row in set (0.01 sec)

字段字符集

使用默认和指定字符集创建的列

  • mysql> create table t3 (a1 varchar(10),a2 varchar(10) character set latin1);

    Query OK, 0 rows affected (0.04 sec)

  • mysql> show create table t3;

+-------+-------------------------------------------------+
| Table | Create Table |
+-------+-------------------------------------------------+
| t3 | CREATE TABLE `t3` (
`a1` varchar(10) default NULL,
`a2` varchar(10) character set latin1 default NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8 |
+-------+-------------------------------------------------+
1 row in set (0.00 sec)

查看列的字符集

  • mysql> show full columns from t3;
+------+------------+------------------+-----+----+--------+------+--------------------------------+--------+
| Field| Type | Collation | Null| Key| Default| Extra| Privileges | Comment|
+------+------------+------------------+-----+----+--------+------+--------------------------------+--------+
| a1 | varchar(10)| utf8_general_ci | YES | | NULL | | select,insert,update,references| |
| a2 | varchar(10)| latin1_swedish_ci| YES | | NULL | | select,insert,update,references| |
+------+------------+------------------+-----+----+--------+------+--------------------------------+--------+
2 rows in set (0.01 sec)

修改列的字符集

  • mysql> alter table t3 change a2 a2 varchar(10) character set utf8;

    Query OK, 0 rows affected (0.03 sec)

    Records: 0 Duplicates: 0 Warnings: 0

  • mysql> show full columns from t3;

+------+------------+----------------+-----+----+--------+------+--------------------------------+--------+
| Field| Type | Collation | Null| Key| Default| Extra| Privileges | Comment|
+------+------------+----------------+-----+----+--------+------+--------------------------------+--------+
| a1 | varchar(10)| utf8_general_ci| YES | | NULL | | select,insert,update,references| |
| a2 | varchar(10)| utf8_general_ci| YES | | NULL | | select,insert,update,references| |
+------+------------+----------------+-----+----+--------+------+--------------------------------+--------+
2 rows in set (0.00 sec)

结论:字符集从数据库、表、列的字符集是逐级继承的关系

命令总结

查看字符集命令

mysql> show create table t4; //显示表字符集
mysql> show create database db2; //显示库字符集
mysql> show full columns from t4; //显示列字符集 alter database db2 default character set utf8; //更改库的字符集
alter table t2 convert to character set latin1;//更改表的现存列字符集
alter table t2 default character set utf8; //更能改表的默认字符集
alter table t3 change a2 a2 varchar(10) character set utf8; //更能改字段的字符集

修改mysql的默认存储引擎

  • mysql> show variables like 'storage%';
+----------------+--------+
| Variable_name | Value |
+----------------+--------+
| storage_engine | MyISAM |
+----------------+--------+
1 row in set (0.01 sec)

在[mysqld]下添加如下参数default-storage-engine=innodb

重启mysql服务,查看

  • mysql> show variables like 'storage%';
+----------------+--------+
| Variable_name | Value |
+----------------+--------+
| storage_engine | InnoDB |
+----------------+--------+
1 row in set (0.01 sec)

创建默认字符集的表

  • mysql> create table t4 (a1 int);

    Query OK, 0 rows affected (0.01 sec)

  • mysql> show create table t4;

+-------+-------------------------------------------+
| Table | Create Table |
+-------+-------------------------------------------+
| t4 | CREATE TABLE `t4` (
`a1` int(11) default NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8 |
+-------+-------------------------------------------+
1 row in set (0.00 sec)

更改表的默认字符集

  • mysql> alter table t4 engine myisam;

    Query OK, 0 rows affected (0.06 sec)

    Records: 0 Duplicates: 0 Warnings: 0

  • mysql> show create table t4;

+-------+-------------------------------------------+
| Table | Create Table |
+-------+-------------------------------------------+
| t4 | CREATE TABLE `t4` (
`a1` int(11) default NULL
) ENGINE=MyISAM DEFAULT CHARSET=utf8 |
+-------+-------------------------------------------+
1 row in set (0.00 sec)

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