mysql查看数据库字符集 查看mysql 字符集

                   修改及查看mysql数据库的字符集

操作系统：Windows Server 2008 R2

Mysql版本：mysql-5.6.29-winx64

事由：MySQL5.6的修改字符集编码为UTF8（解决中文乱码问题）

一、登录MySQL查看用SHOW VARIABLES LIKE ‘character%’;下字符集，显示如下：

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+ --------------------------+----------------------------+ | Variable_name | Value | + --------------------------+----------------------------+ | character_set_client | utf8 | | character_set_connection | utf8 | | character_set_database | latin1 | | character_set_filesystem | binary | | character_set_results | utf8 | | character_set_server | latin1 | | character_set_system | utf8 | | character_sets_dir | /usr/share/mysql/charsets/ | + --------------------------+----------------------------+

 

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1、在[client]字段里加入 default - character - set =utf8，如下： [client] port = 3306 socket = /var/lib/mysql/mysql.sock default - character - set =utf8 2、在[mysqld]字段里加入 character - set -server=utf8，如下： [mysqld] port = 3306 socket = /var/lib/mysql/mysql.sock character - set -server=utf8 3、在[mysql]字段里加入 default - character - set =utf8，如下： [mysql] no -auto-rehash default - character - set =utf8

 

修改完成后，service mysql restart重启mysql服务就生效。注意：[mysqld]字段与[mysql]字段是有区别的。这点在网上没人反馈过。

使用SHOW VARIABLES LIKE ‘character%’;查看，发现 数据库编码全已改成utf8。

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+ --------------------------+----------------------------+ | Variable_name | Value | + --------------------------+----------------------------+ | character_set_client | utf8 | | character_set_connection | utf8 | | character_set_database | utf8 | | character_set_filesystem | binary | | character_set_results | utf8 | | character_set_server | utf8 | | character_set_system | utf8 | | character_sets_dir | /usr/share/mysql/charsets/ | + --------------------------+----------------------------+

 

附My.ini 配置文件内容：

# For advice on how to change settings please see
 # http://dev.mysql.com/doc/refman/5.6/en/server-configuration-defaults.html
 # *** DO NOT EDIT THIS FILE. It's a template which will be copied to the
 # *** default location during install, and will be replaced if you
 # *** upgrade to a newer version of MySQL.
 [WinMySQLAdmin]
 #指定mysql服务启动的启动文件
 Server=D:\MySQL\Mysql-Windows\mysql-5.6.29-winx64\bin\mysql.exe[mysql]
 no-auto-rehash
 default-character-set=utf8

 [mysqld]
 # Remove leading # and set to the amount of RAM for the most important data
 # cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.
 # innodb_buffer_pool_size = 128M
# Remove leading # to turn on a very important data integrity option: logging# changes to the binary log between backups.
 # log_bin

 # These are commonly set, remove the # and set as required.
  basedir = D:\MySQL\Mysql-Windows\mysql-5.6.29-winx64
  datadir = D:\MySQL\Mysql-Windows\mysql-5.6.29-winx64\data
  port = 3306
  server_id = 1
 # default-character-set=gbk
 #default-character-set=utf8
 character-set-server=utf8

 # Remove leading # to set options mainly useful for reporting servers.
 # The server defaults are faster for transactions and fast SELECTs.
 # Adjust sizes as needed, experiment to find the optimal values.
 # join_buffer_size = 128M
 # sort_buffer_size = 2M
 # read_rnd_buffer_size = 2M [client]
 #设置mysql客户端的字符集
 #default-character-set=gbk
 default-character-set=utf8
 #sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES 
//-----------------------------------//

mysql的sql_mode 模式

1. sql_mode模式 
mysql数据库的中有一个环境变量sql_mode,定义了mysql应该支持的sql语法，数据校验等！我们可以通过以下方式查看当前数据库使用的sql_mode： 

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1. mysql> select @@sql_mode;  
2. +----------------------------------------------------------------+  
3. | @@sql_mode                                                     |  
4. +----------------------------------------------------------------+  
5. | STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION |  
6. +----------------------------------------------------------------+

或者通过查看系统变量方式:

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1. mysql> show variables like 'sql_mode%'\G;  
2. *************************** 1. row ***************************  
3. Variable_name: sql_mode  
4.         Value: STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION

mysql5.0以上版本支持三种sql_mode模式：ANSI、TRADITIONAL和STRICT_TRANS_TABLES。 

ANSI模式：宽松模式，对插入数据进行校验，如果不符合定义类型或长度，对数据类型调整或截断保存，报warning警告。 

TRADITIONAL模式：严格模式，当向mysql数据库插入数据时，进行数据的严格校验，保证错误数据不能插入，报error错误。用于事物时，会进行事物的回滚。 

STRICT_TRANS_TABLES模式：严格模式，进行数据的严格校验，错误数据不能插入，报error错误。 

1.2 ANSI模式 

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1. mysql> set @@sql_mode=ANSI;  
2. Query OK, 0 rows affected (0.00 sec)  
3.   
4. mysql> create table test(name varchar(4), pass varchar(4));  
5. Query OK, 0 rows affected (0.03 sec)  
6.   
7. mysql> insert into test values('aaaaa','aaaaa'),('bbbb','bbbb');  
8. Query OK, 2 rows affected, 2 warnings (0.02 sec)  
9. Records: 2  Duplicates: 0  Warnings: 2  
10.   
11. mysql> show warnings;  
12. +---------+------+-------------------------------------------+  
13. | Level   | Code | Message                                   |  
14. +---------+------+-------------------------------------------+  
15. | Warning | 1265 | Data truncated for column 'name' at row 1 |  
16. | Warning | 1265 | Data truncated for column 'pass' at row 1 |  
17. +---------+------+-------------------------------------------+  
18. 2 rows in set (0.00 sec)  
19.   
20. mysql> select * from test;  
21. +------+------+  
22. | name | pass |  
23. +------+------+  
24. | aaaa | aaaa |  
25. | bbbb | bbbb |  
26. +------+------+  
27. 2 rows in set (0.00 sec)

我们可以看到，在ANSI模式下，当我们插入数据时，未满足列长度要求时，数据同样会插入成功，但是对超出列长度的字段进行截断，同时报告warning警告。 

1.3 STRICT_TRANS_TABLES模式

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1. mysql> set @@sql_mode=STRICT_TRANS_TABLES;  
2. Query OK, 0 rows affected (0.00 sec)  
3.   
4. mysql> create table test(name varchar(4), pass varchar(4));  
5. Query OK, 0 rows affected (0.02 sec)  
6.   
7. mysql> insert into test values('aaaaa','aaaaa'),('bbbb','bbbb');  
8. ERROR 1406 (22001): Data too long for column 'name' at row 1  
9.   
10. mysql> show errors;  
11. +-------+------+------------------------------------------+  
12. | Level | Code | Message                                  |  
13. +-------+------+------------------------------------------+  
14. | Error | 1406 | Data too long for column 'name' at row 1 |  
15. +-------+------+------------------------------------------+  
16. 1 row in set (0.00 sec)  
17.   
18. mysql> select * from test;  
19. Empty set (0.00 sec)

我们可以看到，在STRICT_TRANS_TABLES模式下，当我们插入数据时，mysql会严格的进行数据的校验，当发现插入列值未满足要求，直接报告error错误，保证了错误数据无法插入到数据库中。

1.3 TRADITIONAL模式

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1. mysql> set @@sql_mode=TRADITIONAL;  
2. Query OK, 0 rows affected (0.00 sec)  
3.   
4. mysql> create table test(name varchar(4), pass varchar(4));  
5. Query OK, 0 rows affected (0.02 sec)  
6.   
7. mysql> insert into test values('aaaaa','aaaaa'),('bbbb','bbbb');  
8. ERROR 1406 (22001): Data too long for column 'name' at row 1  
9.   
10. mysql> show errors;  
11. +-------+------+------------------------------------------+  
12. | Level | Code | Message                                  |  
13. +-------+------+------------------------------------------+  
14. | Error | 1406 | Data too long for column 'name' at row 1 |  
15. +-------+------+------------------------------------------+  
16. 1 row in set (0.00 sec)  
17.   
18. mysql> select * from test;  
19. Empty set (0.00 sec)

TRADITIONAL模式与STRICT_TRANS_TABLES模式执行的结果，在这种情况下一致。 

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1. mysql> select @@sql_mode\G;  
2. *************************** 1. row ***************************  
3. @@sql_mode: STRICT_TRANS_TABLES,STRICT_ALL_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,E  
4. RROR_FOR_DIVISION_BY_ZERO,TRADITIONAL,NO_AUTO_CREATE_USER  
5. 1 row in set (0.00 sec)

看一下TRADITIONAL模式，我们发现在TRADITIONAL模式下，对所有的事务存储引擎，非事务存储引擎检查，日期类型中的月和日部分不能包含0，不能有0这样的日期(0000-00-00),数据不能除0，禁止grant自动创建新用户等一些校验。

注意：我们这里设置的sql_mode都是session级别的。另外，可以直接修改my.ini文件，找到sql_mode，然后设置新的模式即可！

例如： 

    vi /etc/my.cnf

在[mysqld]下面添加如下列：

sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES