+++ /dev/null
-PostgreSQL 7.0 multi-byte (MB) support README Mar 22 2000
-
- Tatsuo Ishii
- ishii@postgresql.org
- http://www.sra.co.jp/people/t-ishii/PostgreSQL/
-
-0. Introduction
-
-The MB support is intended for allowing PostgreSQL to handle
-multi-byte character sets such as EUC(Extended Unix Code), Unicode and
-Mule internal code. With the MB enabled you can use multi-byte
-character sets in regexp ,LIKE and some other functions. The default
-encoding system chosen is determined while initializing your
-PostgreSQL installation using initdb(1). Note that this can be
-overridden when you create a database using createdb(1) or by using a
-create database SQL command. So you could have multiple databases with
-each different encoding system.
-
-MB also fixes some problems concerning with 8-bit single byte
-character sets including ISO8859. (I would not say all of problems
-have been fixed. I just confirmed that the regression test ran fine
-and a few French characters could be used with the patch. Please let
-me know if you find any problem while using 8-bit characters)
-
-1. How to use
-
-run configure with a multibyte option:
-
- % ./configure --enable-multibyte[=encoding_system]
-
-where the encoding_system is one of:
-
- SQL_ASCII ASCII
- EUC_JP Japanese EUC
- EUC_CN Chinese EUC
- EUC_KR Korean EUC
- EUC_TW Taiwan EUC
- UNICODE Unicode(UTF-8)
- MULE_INTERNAL Mule internal
- LATIN1 ISO 8859-1 English and some European languages
- LATIN2 ISO 8859-2 English and some European languages
- LATIN3 ISO 8859-3 English and some European languages
- LATIN4 ISO 8859-4 English and some European languages
- LATIN5 ISO 8859-5 English and some European languages
- KOI8 KOI8-R
- WIN Windows CP1251
- ALT Windows CP866
-
-Example:
-
- % ./configure --enable-multibyte=EUC_JP
-
-If the encoding system is omitted (./configure --enable-multibyte),
-SQL_ASCII is assumed.
-
-2. How to set the encoding
-
-initdb command defines the default encoding for a PostgreSQL
-installation. For example:
-
- % initdb -E EUC_JP
-
-sets the default encoding to EUC_JP(Extended Unix Code for Japanese).
-Note that you can use "--encoding" instead of "-E" if you like longer
-option string:-) If no -E or --encoding option is given, the encoding
-specified at the compile time is used.
-
-You can create a database with a different encoding.
-
- % createdb -E EUC_KR korean
-
-will create a database named "korean" with EUC_KR encoding. The
-another way to accomplish this is to use a SQL command:
-
- CREATE DATABASE korean WITH ENCODING = 'EUC_KR';
-
-The encoding for a database is represented as "encoding" column in the
-pg_database system catalog. You can see that by using -l or \l of psql
-command.
-
-$ 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
- regression | t-ishii | SQL_ASCII
- template1 | t-ishii | EUC_JP
- test | t-ishii | EUC_JP
- unicode | t-ishii | UNICODE
-(9 rows)
-
-3. Automatic encoding translation between backend and frontend
-
-PostgreSQL supports an automatic encoding translation between backend
-and frontend for some encodings.
-
- encoding of backend available encoding of frontend
- --------------------------------------------------------------------
- EUC_JP EUC_JP, SJIS
-
- EUC_TW EUC_TW, BIG5
-
- LATIN2 LATIN2, WIN1250
-
- LATIN5 LATIN5, WIN, ALT
-
- MULE_INTERNAL EUC_JP, SJIS, EUC_KR, EUC_CN,
- EUC_TW, BIG5, LATIN1 to LATIN5,
- WIN, ALT, WIN1250
-
-To enable the automatic encoding translation, you have to tell
-PostgreSQL the encoding you would like to use in frontend. There are
-several ways to accomplish this.
-
-o using \encoding command in psql
-
-\encoding allows you to change frontend encoding on the fly. For
-example, to change the encoding to SJIS, type:
-
- \encoding SJIS
-
-o using libpq functions
-
-\encoding actually calls PQsetClientEncoding() for its purpose.
-
- int PQsetClientEncoding(PGconn *conn, const char *encoding)
-
-conn is a connection to the backend, and encoding is an encoding you
-want to use. If it successfully sets the encoding, it returns 0,
-otherwise -1. The current encoding for this connection can be shown by
-using:
-
- int PQclientEncoding(const PGconn *conn)
-
-Note that it returns the "encoding id," not the encoding symbol string
-such as "EUC_JP." To convert an encoding id to an encoding symbol, you
-can use:
-
-char *pg_encoding_to_char(int encoding_id)
-
-o using PGCLIENTENCODING
-
-If an environment variable PGCLIENTENCODING is defined in the
-frontend, an automatic encoding translation is done by the backend.
-
-o using SET CLIENT_ENCODING TO command
-
-Setting the frontend side encoding can be done a SQL command:
-
- SET CLIENT_ENCODING TO 'encoding';
-
-Also you can use SQL92 syntax "SET NAMES" for this purpose:
-
- SET NAMES 'encoding';
-
-To query the current the frontend encoding:
-
- SHOW CLIENT_ENCODING;
-
-To return to the default encoding:
-
- RESET CLIENT_ENCODING;
-
-4. About Unicode
-
-An automatic encoding translation between Unicode and any other
-encodings is not supported (yet).
-
-5. What happens if the translation is not possible?
-
-Suppose you choose EUC_JP for the backend, LATIN1 for the frontend,
-then some Japanese characters could not be translated into LATIN1. In
-this case, a letter cannot be represented in the LATIN1 character set,
-would be transformed as:
-
- (HEXA DECIMAL)
-
-6. References
-
-These are good sources to start learning various kind of encoding
-systems.
-
-ftp://ftp.ora.com/pub/examples/nutshell/ujip/doc/cjk.inf
- Detailed explanations of EUC_JP, EUC_CN, EUC_KR, EUC_TW
- appear in section 3.2.
-
-Unicode: http://www.unicode.org/
- The homepage of UNICODE.
-
- RFC 2044
- UTF-8 is defined here.
-
-5. History
-
-May 20, 2000
- * SJIS UDC (NEC selection IBM kanji) support contributed
- by Eiji Tokuya
- * Changes above will appear in 7.0.1
-
-Mar 22, 2000
- * Add new libpq functions PQsetClientEncoding, PQclientEncoding
- * ./configure --with-mb=EUC_JP
- now deprecated. use
- ./configure --enable-multibyte=EUC_JP
- instead
- * Add SQL_ASCII regression test case
- * Add SJIS User Defined Character (UDC) support
- * All of above will appear in 7.0
-
-July 11, 1999
- * Add support for WIN1250 (Windows Czech) as a client encoding
- (contributed by Pavel Behal)
- * fix some compiler warnings (contributed by Tomoaki Nishiyama)
-
-Mar 23, 1999
- * Add support for KOI8(KOI8-R), WIN(CP1251), ALT(CP866)
- (thanks Oleg Broytmann for testing)
- * Fix problem with MB and locale
-
-Jan 26, 1999
- * Add support for Big5 for fronend encoding
- (you need to create a database with EUC_TW to use Big5)
- * Add regression test case for EUC_TW
- (contributed by Jonah Kuo <jonahkuo@mail.ttn.com.tw>)
-
-Dec 15, 1998
- * Bugs related to SQL_ASCII support fixed
-
-Nov 5, 1998
- * 6.4 release. In this version, pg_database has "encoding"
- column that represents the database encoding
-
-Jul 22, 1998
- * determine encoding at initdb/createdb rather than compile time
- * support for PGCLIENTENCODING when issuing COPY command
- * support for SQL92 syntax "SET NAMES"
- * support for LATIN2-5
- * add UNICODE regression test case
- * new test suite for MB
- * clean up source files
-
-Jun 5, 1998
- * add support for the encoding translation between the backend
- and the frontend
- * new command SET CLIENT_ENCODING etc. added
- * add support for LATIN1 character set
- * enhance 8 bit cleaness
-
-April 21, 1998 some enhancements/fixes
- * character_length(), position(), substring() are now aware of
- multi-byte characters
- * add octet_length()
- * add --with-mb option to configure
- * new regression tests for EUC_KR
- (contributed by "Soonmyung. Hong" <hong@lunaris.hanmesoft.co.kr>)
- * add some test cases to the EUC_JP regression test
- * fix problem in regress/regress.sh in case of System V
- * fix toupper(), tolower() to handle 8bit chars
-
-Mar 25, 1998 MB PL2 is incorporated into PostgreSQL 6.3.1
-
-Mar 10, 1998 PL2 released
- * add regression test for EUC_JP, EUC_CN and MULE_INTERNAL
- * add an English document (this file)
- * fix problems concerning 8-bit single byte characters
-
-Mar 1, 1998 PL1 released
-
-Appendix:
-
-[Here is a good documentation explaining how to use WIN1250 on
-Windows/ODBC from Pavel Behal. Please note that Installation step 1)
-is not necceary in 6.5.1 -- Tatsuo]
-
-Version: 0.91 for PgSQL 6.5
-Author: Pavel Behal
-Revised by: Tatsuo Ishii
-Email: behal@opf.slu.cz
-Licence: The Same as PostgreSQL
-
-Sorry for my Eglish and C code, I'm not native :-)
-
-!!!!!!!!!!!!!!!!!!!!!!!!! NO WARRANTY !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
-
-Instalation:
-------------
-1) Change three affected files in source directories
- (I don't have time to create proper patch diffs, I don't know how)
-2) Compile with enabled locale and multibyte set to LATIN2
-3) Setup properly your instalation, do not forget to create locale
- variables in your profile (environment). Ex. (may not be exactly true):
- LC_ALL=cs_CZ.ISO8859-2
- LC_COLLATE=cs_CZ.ISO8859-2
- LC_CTYPE=cs_CZ.ISO8859-2
- LC_MONETARY=cs_CZ.ISO8859-2
- LC_NUMERIC=cs_CZ.ISO8859-2
- LC_TIME=cs_CZ.ISO8859-2
-4) You have to start the postmaster with locales set!
-5) Try it with Czech language, it have to sort
-5) Install ODBC driver for PgSQL into your M$ Windows
-6) Setup properly your data source. Include this line in your ODBC
- configuration dialog in field "Connect Settings:" :
- SET CLIENT_ENCODING = 'WIN1250';
-7) Now try it again, but in Windows with ODBC.
-
-Description:
-------------
-- Depends on proper system locales, tested with RH6.0 and Slackware 3.6,
- with cs_CZ.iso8859-2 loacle
-- Never try to set-up server multibyte database encoding to WIN1250,
- always use LATIN2 instead. There is not WIN1250 locale in Unix
-- WIN1250 encoding is useable only for M$W ODBC clients. The characters are
- on thy fly re-coded, to be displayed and stored back properly
-
-Important:
-----------
-- it reorders your sort order depending on your LC_... setting, so don't be
- confused with regression tests, they don't use locale
-- "ch" is corectly sorted only in some newer locales (Ex. RH6.0)
-- you have to insert money as '162,50' (with comma in aphostrophes!)
-- not tested properly
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