PostgreSQL数据库支持多种字符集,在配置字符集时要分清楚服务器与客户端的字符集,字符集不一致尽管有时能够发生转换,但带来的问题也很头疼。语言环境的配置也很重要。

服务器字符集<来自文档>:
- Name Description Language Server? Bytes/Char Aliases
 - BIG5 Big Five Traditional Chinese No 1-2 WIN950, Windows950
 - EUC_CN Extended UNIX Code-CN Simplified Chinese Yes 1-3
 - EUC_JP Extended UNIX Code-JP Japanese Yes 1-3
 - EUC_JIS_2004 Extended UNIX Code-JP, JIS X 0213 Japanese Yes 1-3
 - EUC_KR Extended UNIX Code-KR Korean Yes 1-3
 - EUC_TW Extended UNIX Code-TW Traditional Chinese, Taiwanese Yes 1-3
 - GB18030 National Standard Chinese No 1-2
 - GBK Extended National Standard Simplified Chinese No 1-2 WIN936, Windows936
 - ISO_8859_5 ISO 8859-5, ECMA 113 Latin/Cyrillic Yes 1
 - ISO_8859_6 ISO 8859-6, ECMA 114 Latin/Arabic Yes 1
 - ISO_8859_7 ISO 8859-7, ECMA 118 Latin/Greek Yes 1
 - ISO_8859_8 ISO 8859-8, ECMA 121 Latin/Hebrew Yes 1
 - JOHAB JOHAB Korean (Hangul) No 1-3
 - KOI8 KOI8-R(U) Cyrillic Yes 1 KOI8R
 - LATIN1 ISO 8859-1, ECMA 94 Western European Yes 1 ISO88591
 - LATIN2 ISO 8859-2, ECMA 94 Central European Yes 1 ISO88592
 - LATIN3 ISO 8859-3, ECMA 94 South European Yes 1 ISO88593
 - LATIN4 ISO 8859-4, ECMA 94 North European Yes 1 ISO88594
 - LATIN5 ISO 8859-9, ECMA 128 Turkish Yes 1 ISO88599
 - LATIN6 ISO 8859-10, ECMA 144 Nordic Yes 1 ISO885910
 - LATIN7 ISO 8859-13 Baltic Yes 1 ISO885913
 - LATIN8 ISO 8859-14 Celtic Yes 1 ISO885914
 - LATIN9 ISO 8859-15 LATIN1 with Euro and accents Yes 1 ISO885915
 - LATIN10 ISO 8859-16, ASRO SR 14111 Romanian Yes 1 ISO885916
 - MULE_INTERNAL Mule internal code Multilingual Emacs Yes 1-4
 - SJIS Shift JIS Japanese No 1-2 Mskanji, ShiftJIS, WIN932, Windows932
 - SHIFT_JIS_2004 Shift JIS, JIS X 0213 Japanese No 1-2
 - SQL_ASCII unspecified (see text) any Yes 1
 - UHC Unified Hangul Code Korean No 1-2
 - WIN949, Windows949UTF8 Unicode, 8-bit all Yes 1-4 Unicode
 - WIN866 Windows CP866 Cyrillic Yes 1 ALTWIN874
 - Windows CP874 Thai Yes 1
 - WIN1250 Windows CP1250 Central European Yes 1
 - WIN1251 Windows CP1251 Cyrillic Yes 1
 - WINWIN1252 Windows CP1252 Western European Yes 1
 - WIN1253 Windows CP1253 Greek Yes 1
 - WIN1254 Windows CP1254 Turkish Yes 1
 - WIN1255 Windows CP1255 Hebrew Yes 1
 - WIN1256 Windows CP1256 Arabic Yes 1
 - WIN1257 Windows CP1257 Baltic Yes 1
 - WIN1258 Windows CP1258 Vietnamese Yes 1 ABC, TCVN, TCVN5712, VSCII
 
常用的简体中文字符集是UTF8和EUC_CN两种。
可自动转换字符集<来自文档>:
- Server Character Set Available Client Character Sets
 - BIG5 not supported as a server encoding
 - EUC_CN EUC_CN, MULE_INTERNAL, UTF8
 - EUC_JP EUC_JP, MULE_INTERNAL, SJIS, UTF8
 - EUC_KR EUC_KR, MULE_INTERNAL, UTF8
 - EUC_TW EUC_TW, BIG5, MULE_INTERNAL, UTF8
 - GB18030 not supported as a server encoding
 - GBK not supported as a server encoding
 - ISO_8859_5 ISO_8859_5, KOI8, MULE_INTERNAL, UTF8, WIN866, WIN1251
 - ISO_8859_6 ISO_8859_6, UTF8
 - ISO_8859_7 ISO_8859_7, UTF8
 - ISO_8859_8 ISO_8859_8, UTF8
 - JOHAB JOHAB, UTF8
 - KOI8 KOI8, ISO_8859_5, MULE_INTERNAL, UTF8, WIN866, WIN1251
 - LATIN1 LATIN1, MULE_INTERNAL, UTF8
 - LATIN2 LATIN2, MULE_INTERNAL, UTF8, WIN1250
 - LATIN3 LATIN3, MULE_INTERNAL, UTF8
 - LATIN4 LATIN4, MULE_INTERNAL, UTF8
 - LATIN5 LATIN5, UTF8
 - LATIN6 LATIN6, UTF8
 - LATIN7 LATIN7, UTF8
 - LATIN8 LATIN8, UTF8
 - LATIN9 LATIN9, UTF8
 - LATIN10 LATIN10, UTF8
 - MULE_INTERNAL MULE_INTERNAL, BIG5, EUC_CN, EUC_JP, EUC_KR, EUC_TW, ISO_8859_5, KOI8, LATIN1 to LATIN4, SJIS, WIN866, WIN1250, WIN1251
 - SJIS not supported as a server encoding
 - SQL_ASCII any (no conversion will be performed)
 - UHC not supported as a server encoding
 - UTF8 all supported encodings
 - WIN866 WIN866, ISO_8859_5, KOI8, MULE_INTERNAL, UTF8, WIN1251
 - WIN874 WIN874, UTF8
 - WIN1250 WIN1250, LATIN2, MULE_INTERNAL, UTF8
 - WIN1251 WIN1251, ISO_8859_5, KOI8, MULE_INTERNAL, UTF8, WIN866
 - WIN1252 WIN1252, UTF8
 - WIN1253 WIN1253, UTF8
 - WIN1254 WIN1254, UTF8
 - WIN1255 WIN1255, UTF8
 - WIN1256 WIN1256, UTF8
 - WIN1257 WIN1257, UTF8
 - WIN1258 WIN1258, UTF8
 
以下针对客户端与服务器字符集配置问题作几个小测试。
测试一:服务器、客户端、语言环境一致的情况
- [postgre@iss3984 ~]$ echo $LANG
 - en_US.UTF-8
 - [postgre@iss3984 ~]$ psql daduxiong
 - Welcome to psql 8.3.11 (server 8.3.10), the PostgreSQL interactive terminal.
 - Type:
 - \copyright for distribution terms
 - \h for help with SQL commands
 - \? for help with psql commands
 - \g or terminate with semicolon to execute query
 - \q to quitdaduxiong=# \l
 - List of databases
 - Name | Owner | Encoding
 - -----------+---------+----------
 - daduxiong | postgre | UTF8
 - postgres | postgre | UTF8
 - template0 | postgre | UTF8
 - template1 | postgre | UTF8(4 rows)
 - daduxiong=# show client_encoding;
 - client_encoding-----------------
 - UTF8(1 row)daduxiong=# insert into t1 values (1,'中国');
 - INSERT 0 1
 - daduxiong=# select * from t1; id |
 - name
 - ----+------------------------
 - 1 | 中国 (1 row)
 
服务器与客户端字符集相同,在数据录入时不发生字符集转换;因语言环境也相同所以展现不会出现乱码。
测试二:客户端与服务器、语言环境不一致的情况
- daduxiong=# \encoding
 - GBKdaduxiong=# show
 - client_encoding;
 - client_encoding-----------------
 - GBK(1 row)
 - daduxiong=# insert into t1 values (2,'日本');
 - INSERT 0 1daduxiong=# select * from t1;
 - id | name
 - ----+-------------------------
 - 1 | �й�
 - 2 | 日本 (2 rows)
 
客户端与服务器的字符集不一致,在数据录入时将发生字符集转换;当前展现的第二条记录非乱码形式是因为客户端字符集为GBK,在UTF8下同样出现乱码,在使用时需要语言环境进行配置。
测试三:服务器与客户端、语言环境不一致的情况
- daduxiong=# \q
 - [postgre@iss3984 ~]$ LANG=GBK export LANG
 - [postgre@iss3984 ~]$ echo $LANG
 - GBK
 - [postgre@iss3984 ~]$ psql daduxiong
 - Welcome to psql 8.3.11 (server 8.3.10), the PostgreSQL interactive terminal.
 - Type:
 - \copyright for distribution terms
 - \h for help with SQL commands
 - \? for help with psql commands
 - \g or terminate with semicolon to execute query
 - \q to quitdaduxiong=# show client_encoding;
 - client_encoding
 - -----------------
 - UTF8
 - (1 row)
 - daduxiong=# \encoding GBK
 - daduxiong=# select * from t1;
 - id | name
 - ----+-------------------------
 - 1 | �й�
 - 2 | 日本
 - (2 rows)
 - daduxiong=# insert into t1 values (3,'美国');
 - INSERT 0 1daduxiong=# select * from t1;
 - id | name
 - ----+-------------------------
 - 1 | �й�
 - 2 | 日本
 - 3 | 美国
 - (3 rows)daduxiong=# \q
 
客户端、语言环境均配置为GBK字符集,在当前环境下展现的为非乱码形式,数据录入时将发生字符集转换。
测试四:服务器与客户端、语言环境恢复一致的情况
- [postgre@iss3984 ~]$ LANG=en_US.UTF8 export LANG
 - [postgre@iss3984 ~]$ psql daduxiong
 - Welcome to psql 8.3.11 (server 8.3.10), the PostgreSQL interactive terminal.
 - Type: \copyright for distribution terms
 - \h for help with SQL commands
 - \? for help with psql commands
 - \g or terminate with semicolon to execute query
 - \q to quitdaduxiong=# show client_encoding; client_encoding
 - -----------------
 - UTF8(1 row)
 - daduxiong=# select * from t1;
 - id | name
 - ----+-------------------------
 - 1 | 中国
 - 2 | 鏃ユ湰
 - 3 | 缇庡浗
 - (3 rows)daduxiong=#
 
通过恢复原始的PostgreSQL字符集状态,所有环境均为UTF8字符集,此时发现经过字符集转换后的内容为乱码。