查看和設置MySQL數據庫字符集(轉)

查看和設置MySQL數據庫字符集
作者:scorpio 2008-01-21 10:05:17
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Liunx下修改MySQL字符集:
1.查找MySQL的cnf文件的位置
find / -iname '*.cnf' -print
/usr/share/mysql/my-innodb-heavy-4G.cnf
/usr/share/mysql/my-large.cnf
/usr/share/mysql/my-small.cnf
/usr/share/mysql/my-medium.cnf
/usr/share/mysql/my-huge.cnf
/usr/share/texmf/web2c/texmf.cnf
/usr/share/texmf/web2c/mktex.cnf
/usr/share/texmf/web2c/fmtutil.cnf
/usr/share/texmf/tex/xmltex/xmltexfmtutil.cnf
/usr/share/texmf/tex/jadetex/jadefmtutil.cnf
/usr/share/doc/MySQL-server-community-5.1.22/my-innodb-heavy-4G.cnf
/usr/share/doc/MySQL-server-community-5.1.22/my-large.cnf
/usr/share/doc/MySQL-server-community-5.1.22/my-small.cnf
/usr/share/doc/MySQL-server-community-5.1.22/my-medium.cnf
/usr/share/doc/MySQL-server-community-5.1.22/my-huge.cnf

 

2. 拷貝 small.cnf、my-medium.cnf、my-huge.cnf、my-innodb-heavy-4G.cnf其中的一個到/etc下,命名爲my.cnf
cp /usr/share/mysql/my-medium.cnf /etc/my.cnf

 

3. 修改my.cnf

vi /etc/my.cnf

在[client]下添加
default-character-set=utf8

在[mysqld]下添加
default-character-set=utf8

 

4.重新啓動MySQL
[root@bogon ~]# /etc/rc.d/init.d/mysql restart
Shutting down MySQL                                        [ 確定 ]
Starting MySQL.                                            [ 確定 ]
[root@bogon ~]# mysql -u root -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or /g.
Your MySQL connection id is 1
Server version: 5.1.22-rc-community-log MySQL Community Edition (GPL)

Type 'help;' or '/h' for help. Type '/c' to clear the buffer.

 

5.查看字符集設置

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 (0.02 sec)

mysql> show variables like 'character_set_%';
+--------------------------+----------------------------+
| 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/ |
+--------------------------+----------------------------+
8 rows in set (0.02 sec)

mysql>

其他的一些設置方法:
修改數據庫的字符集
   mysql>use mydb
   mysql>alter database mydb character set utf-8;

創建數據庫指定數據庫的字符集
   mysql>create database mydb character set utf-8;

通過配置文件修改:

修改/var/lib/mysql/mydb/db.opt
default-character-set=latin1
default-collation=latin1_swedish_ci

default-character-set=utf8
default-collation=utf8_general_ci

重起MySQL:
[root@bogon ~]# /etc/rc.d/init.d/mysql restart

 

通過MySQL命令行修改:

mysql> set character_set_client=utf8;
Query OK, 0 rows affected (0.00 sec)

mysql> set character_set_connection=utf8;
Query OK, 0 rows affected (0.00 sec)

mysql> set character_set_database=utf8;
Query OK, 0 rows affected (0.00 sec)

mysql> set character_set_results=utf8;
Query OK, 0 rows affected (0.00 sec)

mysql> set character_set_server=utf8;
Query OK, 0 rows affected (0.00 sec)

mysql> set character_set_system=utf8;
Query OK, 0 rows affected (0.01 sec)

mysql> set collation_connection=utf8;
Query OK, 0 rows affected (0.01 sec)

mysql> set collation_database=utf8;
Query OK, 0 rows affected (0.01 sec)

mysql> set collation_server=utf8;
Query OK, 0 rows affected (0.01 sec)


查看:
mysql> show variables like 'character_set_%';
+--------------------------+----------------------------+
| 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/ |
+--------------------------+----------------------------+
8 rows in set (0.03 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 (0.04 sec)

 

 

 

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【知識性文章轉載】

MYSQL 字符集問題

 

 

MySQL的字符集支持(Character Set Support)有兩個方面:

     字符集(Character set)和排序方式(Collation)。

對於字符集的支持細化到四個層次:

     服務器(server),數據庫(database),數據表(table)和連接(connection)。

1.MySQL默認字符集

MySQL對於字符集的指定可以細化到一個數據庫,一張表,一列,應該用什麼字符集。

但是,傳統的程序在創建數據庫和數據表時並沒有使用那麼複雜的配置,它們用的是默認的配置,那麼,默認的配置從何而來呢?    (1)編譯MySQL 時,指定了一個默認的字符集,這個字符集是 latin1;

    (2)安裝MySQL 時,可以在配置文件 (my.ini) 中指定一個默認的的字符集,如果沒指定,這個值繼承自編譯時指定的;

    (3)啓動mysqld 時,可以在命令行參數中指定一個默認的的字符集,如果沒指定,這個值繼承自配置文件中的配置,此時 character_set_server 被設定爲這個默認的字符集;

    (4)當創建一個新的數據庫時,除非明確指定,這個數據庫的字符集被缺省設定爲character_set_server;

    (5)當選定了一個數據庫時,character_set_database 被設定爲這個數據庫默認的字符集;

    (6)在這個數據庫裏創建一張表時,表默認的字符集被設定爲 character_set_database,也就是這個數據庫默認的字符集;

    (7)當在表內設置一欄時,除非明確指定,否則此欄缺省的字符集就是表默認的字符集;

簡單的總結一下,如果什麼地方都不修改,那麼所有的數據庫的所有表的所有欄位的都用 latin1 存儲,不過我們如果安裝 MySQL,一般都會選擇多語言支持,也就是說,安裝程序會自動在配置文件中把 default_character_set 設置爲 UTF-8,這保證了缺省情況下,所有的數據庫的所有表的所有欄位的都用 UTF-8 存儲。

2.查看默認字符集(默認情況下,mysql的字符集是latin1(ISO_8859_1)

通常,查看系統的字符集和排序方式的設定可以通過下面的兩條命令:

     mysql> SHOW VARIABLES LIKE 'character%';

+--------------------------+---------------------------------+

| Variable_name            | Value                           |

+--------------------------+---------------------------------+

| character_set_client     | latin1                          |

| character_set_connection | latin1                          |

| character_set_database   | latin1                          |

| character_set_filesystem | binary                    |

| character_set_results    | latin1                          |

| character_set_server     | latin1                          |

| character_set_system    | utf8                            |

| character_sets_dir       | D:"mysql-5.0.37"share"charsets" |

+--------------------------+---------------------------------+

mysql> SHOW VARIABLES LIKE 'collation_%';

+----------------------+-----------------+

| Variable_name        | Value           |

+----------------------+-----------------+

| collation_connection | utf8_general_ci |

| collation_database   | utf8_general_ci |

| collation_server     | utf8_general_ci |

+----------------------+-----------------+

3.修改默認字符集

(1) 最簡單的修改方法,就是修改mysql的my.ini文件中的字符集鍵值,

如    default-character-set = utf8

      character_set_server = utf8

   修改完後,重啓mysql的服務,service mysql restart

   使用 mysql> SHOW VARIABLES LIKE 'character%';查看,發現數據庫編碼均已改成utf8

+--------------------------+---------------------------------+

| 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       | D:"mysql-5.0.37"share"charsets" |

+--------------------------+---------------------------------+

   (2) 還有一種修改字符集的方法,就是使用mysql的命令

   mysql> SET character_set_client = utf8 ;

     mysql> SET character_set_connection = utf8 ;

     mysql> SET character_set_database = utf8 ;

     mysql> SET character_set_results = utf8 ;

     mysql> SET character_set_server = utf8 ;

     mysql> SET collation_connection = utf8 ;

     mysql> SET collation_database = utf8 ;

     mysql> SET collation_server = utf8 ;

一般就算設置了表的默認字符集爲utf8並且通過UTF-8編碼發送查詢,你會發現存入數據庫的仍然是亂碼。問題就出在這個connection連接層上。解決方法是在發送查詢前執行一下下面這句:

SET NAMES 'utf8';它相當於下面的三句指令:

SET character_set_client = utf8;

SET character_set_results = utf8;

SET character_set_connection = utf8;

總結:

因此,使用什麼數據庫版本,不管是3.x,還是4.0.x還是4.1.x,其實對我們來說不重要,重要的有二:

1) 正確的設定數據庫編碼.MySQL4.0以下版本的字符集總是默認ISO8859-1,MySQL4.1在安裝的時候會讓你選擇。如果你準備使用UTF- 8,那麼在創建數據庫的時候就要指定好UTF-8(創建好以後也可以改,4.1以上版本還可以單獨指定表的字符集)

2) 正確的設定數據庫connection編碼.設置好數據庫的編碼後,在連接數據庫時候,應該指定connection的編碼,比如使用jdbc連接時,指定連接爲utf8方式.

來自: http://hi.baidu.com/ak456/blog/item/2ead648b61330b16c8fc7a80.html
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