Mysql 字符集研究
2015-08-07 13:50
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mysql> show databases ; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | test | +--------------------+ 4 rows in set (0.00 sec) mysql> use information_schema ; Reading table information for completion of table and column names You can turn off this feature to get a quicker startup with -A Database changed mysql> use information_schema ; Database changed mysql> select * from CHARACTER_SETS ; ----- 字符集 符(Character)是各种文字和符号的总称，包括各国家文字、标点符号、图形符号、数字等。 -----字符集(Character set)是多个字符的集合，字符集种类较多，每个字符集包含的字符个数不同，常见字符集名称：ASCII字符集、GB2312字符集、BIG5字符集、 GB18030字符集、Unicode字符集等。 -----计算机要准确的处理各种字符集文字，需要进行字符编码，以便计算机能够识别和存储各种文字。 -- CHARACTER_SET_NAME 字符集名称 -- 默认的校验规则 -- 字符集描述 -- 单个字符可占用的最多字节数 +--------------------+----------------------+-----------------------------+--------+ | CHARACTER_SET_NAME | DEFAULT_COLLATE_NAME | DESCRIPTION | MAXLEN | +--------------------+----------------------+-----------------------------+--------+ | big5 | big5_chinese_ci | Big5 Traditional Chinese | 2 | | dec8 | dec8_swedish_ci | DEC West European | 1 | | cp850 | cp850_general_ci | DOS West European | 1 | | hp8 | hp8_english_ci | HP West European | 1 | | koi8r | koi8r_general_ci | KOI8-R Relcom Russian | 1 | | latin1 | latin1_swedish_ci | cp1252 West European | 1 | | latin2 | latin2_general_ci | ISO 8859-2 Central European | 1 | | swe7 | swe7_swedish_ci | 7bit Swedish | 1 | | ascii | ascii_general_ci | US ASCII | 1 | | ujis | ujis_japanese_ci | EUC-JP Japanese | 3 | | sjis | sjis_japanese_ci | Shift-JIS Japanese | 2 | | hebrew | hebrew_general_ci | ISO 8859-8 Hebrew | 1 | | tis620 | tis620_thai_ci | TIS620 Thai | 1 | | euckr | euckr_korean_ci | EUC-KR Korean | 2 | | koi8u | koi8u_general_ci | KOI8-U Ukrainian | 1 | | gb2312 | gb2312_chinese_ci | GB2312 Simplified Chinese | 2 | | greek | greek_general_ci | ISO 8859-7 Greek | 1 | | cp1250 | cp1250_general_ci | Windows Central European | 1 | | gbk | gbk_chinese_ci | GBK Simplified Chinese | 2 | | latin5 | latin5_turkish_ci | ISO 8859-9 Turkish | 1 | | armscii8 | armscii8_general_ci | ARMSCII-8 Armenian | 1 | | utf8 | utf8_general_ci | UTF-8 Unicode | 3 | | ucs2 | ucs2_general_ci | UCS-2 Unicode | 2 | | cp866 | cp866_general_ci | DOS Russian | 1 | | keybcs2 | keybcs2_general_ci | DOS Kamenicky Czech-Slovak | 1 | | macce | macce_general_ci | Mac Central European | 1 | | macroman | macroman_general_ci | Mac West European | 1 | | cp852 | cp852_general_ci | DOS Central European | 1 | | latin7 | latin7_general_ci | ISO 8859-13 Baltic | 1 | | utf8mb4 | utf8mb4_general_ci | UTF-8 Unicode | 4 | | cp1251 | cp1251_general_ci | Windows Cyrillic | 1 | | utf16 | utf16_general_ci | UTF-16 Unicode | 4 | | utf16le | utf16le_general_ci | UTF-16LE Unicode | 4 | | cp1256 | cp1256_general_ci | Windows Arabic | 1 | | cp1257 | cp1257_general_ci | Windows Baltic | 1 | | utf32 | utf32_general_ci | UTF-32 Unicode | 4 | | binary | binary | Binary pseudo charset | 1 | | geostd8 | geostd8_general_ci | GEOSTD8 Georgian | 1 | | cp932 | cp932_japanese_ci | SJIS for Windows Japanese | 2 | | eucjpms | eucjpms_japanese_ci | UJIS for Windows Japanese | 3 | +--------------------+----------------------+-----------------------------+--------+ mysql> show character set ; +----------+-----------------------------+---------------------+--------+ | Charset | Description | Default collation | Maxlen | +----------+-----------------------------+---------------------+--------+ | big5 | Big5 Traditional Chinese | big5_chinese_ci | 2 | | dec8 | DEC West European | dec8_swedish_ci | 1 | | cp850 | DOS West European | cp850_general_ci | 1 | | hp8 | HP West European | hp8_english_ci | 1 | | koi8r | KOI8-R Relcom Russian | koi8r_general_ci | 1 | | latin1 | cp1252 West European | latin1_swedish_ci | 1 | | latin2 | ISO 8859-2 Central European | latin2_general_ci | 1 | | swe7 | 7bit Swedish | swe7_swedish_ci | 1 | | ascii | US ASCII | ascii_general_ci | 1 | | ujis | EUC-JP Japanese | ujis_japanese_ci | 3 | | sjis | Shift-JIS Japanese | sjis_japanese_ci | 2 | | hebrew | ISO 8859-8 Hebrew | hebrew_general_ci | 1 | | tis620 | TIS620 Thai | tis620_thai_ci | 1 | | euckr | EUC-KR Korean | euckr_korean_ci | 2 | | koi8u | KOI8-U Ukrainian | koi8u_general_ci | 1 | | gb2312 | GB2312 Simplified Chinese | gb2312_chinese_ci | 2 | | greek | ISO 8859-7 Greek | greek_general_ci | 1 | | cp1250 | Windows Central European | cp1250_general_ci | 1 | | gbk | GBK Simplified Chinese | gbk_chinese_ci | 2 | | latin5 | ISO 8859-9 Turkish | latin5_turkish_ci | 1 | | armscii8 | ARMSCII-8 Armenian | armscii8_general_ci | 1 | | utf8 | UTF-8 Unicode | utf8_general_ci | 3 | | ucs2 | UCS-2 Unicode | ucs2_general_ci | 2 | | cp866 | DOS Russian | cp866_general_ci | 1 | | keybcs2 | DOS Kamenicky Czech-Slovak | keybcs2_general_ci | 1 | | macce | Mac Central European | macce_general_ci | 1 | | macroman | Mac West European | macroman_general_ci | 1 | | cp852 | DOS Central European | cp852_general_ci | 1 | | latin7 | ISO 8859-13 Baltic | latin7_general_ci | 1 | | utf8mb4 | UTF-8 Unicode | utf8mb4_general_ci | 4 | | cp1251 | Windows Cyrillic | cp1251_general_ci | 1 | | utf16 | UTF-16 Unicode | utf16_general_ci | 4 | | utf16le | UTF-16LE Unicode | utf16le_general_ci | 4 | | cp1256 | Windows Arabic | cp1256_general_ci | 1 | | cp1257 | Windows Baltic | cp1257_general_ci | 1 | | utf32 | UTF-32 Unicode | utf32_general_ci | 4 | | binary | Binary pseudo charset | binary | 1 | | geostd8 | GEOSTD8 Georgian | geostd8_general_ci | 1 | | cp932 | SJIS for Windows Japanese | cp932_japanese_ci | 2 | | eucjpms | UJIS for Windows Japanese | eucjpms_japanese_ci | 3 | +----------+-----------------------------+---------------------+--------+ 字符集相关参数 · character_set_client 来自客户端的语句的字符集。 · character_set_connection 用于没有字符集导入符的文字和数字－字符串转换。 · character_set_database 默认数据库使用的字符集。当默认数据库更改时，服务器则设置该变量。如果没有默认数据库，变量的值同character_set_server。 · character_set_results 用于向客户端返回查询结果的字符集。 · character_set_ server 服务器的默认字符集。 · character_set_system 服务器用来保存识别符的字符集。该值一定是utf8。 · character_sets_dir 字符集安装目录。 推荐所有参数设置的字符集相同以避免乱码 字符集参数的修改 1 修改mysqld启动选项 [mysql@server ~]$ mysqld --defaults-file=/home/mysql/my.cnf --character-set-server=latin1 >> 1.log & mysql> show variables like 'character%' ; +--------------------------+---------------------------------+ | 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 | /mysql/software/share/charsets/ | 2 修改参数文件 [mysql@server ~]$ vi my.cnf [mysqld_mulit] mysqld = /mysql/software/bin/mysqld_safe mysqladmin = /mysql/software/bin/mysqladmin [mysqld] socket = /mysql/data/db_3306/mysql3306.sock port = 3306 pid-file = /mysql/data/db_3306/mysq3306.pid datadir = /mysql/data/db_3306 character_set_server = latin1 [mysqld3306] socket = /mysql/data/db_3306/mysql3306.sock port = 3306 pid-file = /mysql/data/db_3306/mysq3306.pid datadir = /mysql/data/db_3306 [mysqld3307] socket = /mysql/data/db_3307/mysql3307.sock port = 3307 pid-file = /mysql/data/db_3307/mysq3307.pid datadir = /mysql/data/db_3307 [mysqld3308] socket = /mysql/data/db_3308/mysql3308.sock port = 3308 pid-file = /mysql/data/db_3308/mysq3308.pid datadir = /mysql/data/db_3308 [mysql@server ~]$ mysqld --defaults-file=/home/mysql/my.cnf >> 1.log & [1] 6827 [mysql@server ~]$ 2015-08-07 11:15:22 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details). 2015-08-07 11:15:22 0 [Note] mysqld (mysqld 5.6.26) starting as process 6827 ... 2015-08-07 11:15:22 6827 [Note] Plugin 'FEDERATED' is disabled. 2015-08-07 11:15:22 6827 [Note] InnoDB: Using atomics to ref count buffer pool pages 2015-08-07 11:15:22 6827 [Note] InnoDB: The InnoDB memory heap is disabled 2015-08-07 11:15:22 6827 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins 2015-08-07 11:15:22 6827 [Note] InnoDB: Memory barrier is not used 2015-08-07 11:15:22 6827 [Note] InnoDB: Compressed tables use zlib 1.2.3 2015-08-07 11:15:22 6827 [Note] InnoDB: Using Linux native AIO 2015-08-07 11:15:22 6827 [Note] InnoDB: Using CPU crc32 instructions 2015-08-07 11:15:22 6827 [Note] InnoDB: Initializing buffer pool, size = 128.0M 2015-08-07 11:15:22 6827 [Note] InnoDB: Completed initialization of buffer pool 2015-08-07 11:15:22 6827 [Note] InnoDB: Highest supported file format is Barracuda. 2015-08-07 11:15:22 6827 [Note] InnoDB: 128 rollback segment(s) are active. 2015-08-07 11:15:22 6827 [Note] InnoDB: Waiting for purge to start 2015-08-07 11:15:22 6827 [Note] InnoDB: 5.6.26 started; log sequence number 1626107 2015-08-07 11:15:22 6827 [Note] Server hostname (bind-address): '*'; port: 3306 2015-08-07 11:15:22 6827 [Note] IPv6 is not available. 2015-08-07 11:15:22 6827 [Note] - '0.0.0.0' resolves to '0.0.0.0'; 2015-08-07 11:15:22 6827 [Note] Server socket created on IP: '0.0.0.0'. 2015-08-07 11:15:22 6827 [Note] Event Scheduler: Loaded 0 events 2015-08-07 11:15:22 6827 [Note] mysqld: ready for connections. Version: '5.6.26' socket: '/mysql/data/db_3306/mysql3306.sock' port: 3306 Source distribution [mysql@server ~]$ [mysql@server ~]$ [mysql@server ~]$ [mysql@server ~]$ mysql -uroot -S /mysql/data/db_3306/mysql3306.sock Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 1 Server version: 5.6.26 Source distribution Copyright (c) 2000, 2015, 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 'character%' ; +--------------------------+---------------------------------+ | 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 | /mysql/software/share/charsets/ | +--------------------------+---------------------------------+ 8 rows in set (0.00 sec) mysql> 各个层级字符集设置 1 实例级 参见上文 2 数据库级别 mysql> CREATE DATABASE dao CHARACTER set utf32 ; Query OK, 1 row affected (0.01 sec) mysql> use dao ; Database changed mysql> show create database dao ; +----------+---------------------------------------------------------------+ | Database | Create Database | +----------+---------------------------------------------------------------+ | dao | CREATE DATABASE `dao` /*!40100 DEFAULT CHARACTER SET utf32 */ | +----------+---------------------------------------------------------------+ 1 row in set (0.00 sec) 3 表级别 mysql> create table dao_test1 (a varchar(10)) default charset=utf8; Query OK, 0 rows affected (0.05 sec) mysql> show create table dao_test1 ; +-----------+------------------------------------------------------------------------------------------------+ | Table | Create Table | +-----------+------------------------------------------------------------------------------------------------+ | dao_test1 | CREATE TABLE `dao_test1` ( `a` varchar(10) DEFAULT NULL ) ENGINE=InnoDB DEFAULT CHARSET=utf8 | +-----------+------------------------------------------------------------------------------------------------+ 1 row in set (0.00 sec) 4 列级别 mysql> create table dao_test2 (a varchar(10) CHARACTER SET utf16 ,b varchar(100)) ; Query OK, 0 rows affected (0.01 sec) mysql> show create table dao_test2 ; +-----------+------------------------------------------------------------------------------------------------------------------------------------------------------+ | Table | Create Table | +-----------+------------------------------------------------------------------------------------------------------------------------------------------------------+ | dao_test2 | CREATE TABLE `dao_test2` ( `a` varchar(10) CHARACTER SET utf16 DEFAULT NULL, `b` varchar(100) DEFAULT NULL ) ENGINE=InnoDB DEFAULT CHARSET=utf32 | +-----------+------------------------------------------------------------------------------------------------------------------------------------------------------+ 1 row in set (0.00 sec)
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