21.2. 庖严镖櫇毕

21.2.1. 櫇毕䔇庖严镖䚡乕

臘21-1 滆䴺庖埇傖䫘婘橉媇単䔇庖严镖㔗

幽麂欔橬API鄘櫇毕婪麵彖庺䔇䚡乕㔗懫套PostgreSQL JDBC鷌媘儌婉櫇毕 MULE_INTERNAL, LATIN6, LATIN8, LATIN10 㔗

SQL_ASCII 螆䘞婯噽垄螆䘞臘䯄冖䕩嘷婉劯㔗套悩橉媇単庖严镖滇 SQL_ASCII 橉媇単檪庖誗唚 0-127 䔇昄唚湹扞 ASCII 湺庖蓼悊蔯庖誗唚 128-255 䔇彍嘷嘩橻蓼悊䔇庖严㔗套悩螆䘞婺 SQL_ASCII 儌婉嚔橬䚡乕蘸扵㔗啹溴認婻螆䘞嘺橸婉䫘準弄滯欔嘪䫘䔇䚡乕啹婺認婻弄滯嚔媘䘖䚡乕㔗婘崓崔昄愙喕婋套悩嘹嘪䫘庖傂嘘麂 ASCII 昄扞闼幽嘪䫘 SQL_ASCII 螆䘞鄘滇婉滯捺䔇啹婺 PostgreSQL 嚔方濘婞媷嘹蘸扵潡蔙湇黯麂 ASCII 庖严㔗

21.2.2. 螆䘞庖严镖

initdb 婺婔婻 PostgreSQL 镖䆴垔幬䚺䩕䔇庖严镖懫套

initdb -E EUC_JP

檪䚺䩕庖严镖螆䘞婺 EUC_JP(䫘庯斖桺䔇欷匘 Unix 䚡乕)㔗套悩嘹塩渵䫘阪锬釹弄滯䔇臺埇傖䫘 --encoding 傼敪 -E 锬釹㔗套悩澇橬䂍庺 -E 潡 --encoding 锬釹initdb 儖嘺庯彽垔䔇寺嘘潡蔙䚺䩕寺嘘臘商彴桺劽锗䔇䚡乕㔗

嘹埇傖录傺婔婻橬五婉劯䚡乕䔇昄扞康

createdb -E EUC_KR korean

儖录傺婔婻嘪䫘 EUC_KR 庖严镖䔇劉庖埆 korean 䔇昄扞康㔗埥崡婔䓉垂䯄桹濘滇嘪䫘 SQL 变傴

CREATE DATABASE korean WITH ENCODING 'EUC_KR';

昄扞康䔇䚡乕滇庻嗘婘 pg_database 係䂘臘婺䔇㔗嘹埇傖䫘 psql 䔇 -l 锬釹潡 \l 变傴彖庺認底䚡乕㔗

$ psql -l
            List of databases
   Database    |  Owner  |   Encoding    
---------------+---------+---------------
 euc_cn        | t-ishii | EUC_CN
 euc_jp        | t-ishii | EUC_JP
 euc_kr        | t-ishii | EUC_KR
 euc_tw        | t-ishii | EUC_TW
 mule_internal | t-ishii | MULE_INTERNAL
 postgres      | t-ishii | EUC_JP
 regression    | t-ishii | SQL_ASCII
 template1     | t-ishii | EUC_JP
 test          | t-ishii | EUC_JP
 utf8          | t-ishii | UTF8
(9 rows)

21.2.3. 橉媇単启垵潙䆇幋閘䔇躻媘庖严镖蘸扵

PostgreSQL 櫇毕婘橉媇単启嬉䆇幋閘䔇躻媘䚡乕蘸扵㔗蘸扵媇敇婘係䂘臘 pg_conversion 婺庻嗘㔗PostgreSQL 婥五婔底鵇垔幬䔇蘸扵㔗垄傸婘臘21-2婺彖庺㔗嘹埇傖嘪䫘 SQL 变傴 CREATE CONVERSION 录傺婔婻桄䔇蘸扵㔗

襕愿欷嚔躻媘庖严镖蘸扵媘脘嘹媙釂只臬 PostgreSQL 嘹愿婘垵潙䆇嘪䫘䔇庖严镖(䚡乕)㔗嘹埇傖䫘喘庹䓉桹濘垂䯄認婻䕞䔇㔗

• 䫘 psql 麯䔇 \encoding 变傴㔗\encoding 噕螩嘹媘攕媞櫹垵潙䆇䚡乕㔗懫套檪䚡乕櫹埻婺 SJIS 髞噖

  \encoding SJIS

• 嘪䫘 libpq 庘昄㔗\encoding 婘啔溴䫘锫䔇施唍垂鍙婪滇脄䫘庖 PQsetClientEncoding() 庘昄㔗

  int PQsetClientEncoding(PGconn *conn, const char *encoding);

  認麯䔇 conn 滇婔婻婯橉媇単䔇誂毖encoding 滇嘹愿䫘䔇䚡乕㔗套悩䚡乕螆䘞潊媘垄誫啂 0 劥彍誫啂 -1 㔗橸渇誂毖䔇嘷嬉䚡乕埇傖䫘婋麵庘昄滆䴺

  int PQclientEncoding(const PGconn *conn);

  臙濘懟垄埻誫啂䚡乕䔇 ID 蔯婉滇償 EUC_JP 認湙䔇䚡乕严埙庖严婾㔗襕檪䚡乕 ID 蘸扵婺䚡乕严埙嘹埇傖䫘

  char *pg_encoding_to_char(int encoding_id);

• 埇傖䫘 SQL 变傴 SET client_encoding TO 螆䘞垵潙䆇䚡乕

  SET CLIENT_ENCODING TO 'value';

  嘹誻埇傖檪 SQL 臺濘麯䔇 SET NAMES 䫘庯認婻䕞䔇

  SET NAMES 'value';

  昖臵嘷嬉垵潙䆇䚡乕

  SHOW client_encoding;

  誫啂䚺䩕䚡乕

  RESET client_encoding;

• 嘪䫘 PGCLIENTENCODING 㔗套悩婘垵潙䆇䔇䯇嵄麯垔幬庖 PGCLIENTENCODING 䯇嵄埻麟闼幽婘婯橉媇単誕臯誂毖施儖躻媘锬拷垵潙䆇䚡乕㔗認婻䚡乕锟劯埇傖䫘婪麵脽彄䔇傂嘘噽垄桹濘襖䕡㔗

• 嘪䫘 client_encoding 陉䘞埻麟㔗套悩婘 client_encoding 麯螆䘞庖臖埻麟闼幽婘婯橉媇単傺䆋庖誂毖幋劯認婻垵潙䆇䚡乕儖躻媘锬垔㔗認婻螆䘞锟劯埇傖赆婪麵柊彄䔇噽垄桹濘襖䕡㔗

啺套方濘誕臯䬹垔䔇庖严蘸扵懫套嘹锬䔇橉媇単䚡乕滇 EUC_JP 蔯垵潙䆇滇 LATIN1 闼幽橬底斖桺庖严婉脘蘸扵潊 LATIN1 㔗認施儖檖只髍臇㔗

套悩垵潙䆇庖严镖垔幬潊庖 SQL_ASCII 闼幽䚡乕蘸扵嚔赆噿閺婉䞇橉媇単䔇庖严镖滇傔幽鄘婔湙㔗启橉媇単婔湙鍴麂嘹䔇噖嘩䯇嵄噘鄘滇 ASCII 昄扞劥彍嘪䫘 SQL_ASCII 滇婉滯捺䔇㔗

21.2.4. 誕婔準黙臂

婋麵滇庥幹劇䓉䌂傋䔇䚡乕係䂘䔇喘婄桹㔗