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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>23.3. Character Set Support</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="collation.html" title="23.2. Collation Support" /><link rel="next" href="maintenance.html" title="Chapter 24. Routine Database Maintenance Tasks" /></head><body><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">23.3. Character Set Support</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="collation.html" title="23.2. Collation Support">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="charset.html" title="Chapter 23. Localization">Up</a></td><th width="60%" align="center">Chapter 23. Localization</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 11.5 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="maintenance.html" title="Chapter 24. Routine Database Maintenance Tasks">Next</a></td></tr></table><hr></hr></div><div class="sect1" id="MULTIBYTE"><div class="titlepage"><div><div><h2 class="title" style="clear: both">23.3. Character Set Support</h2></div></div></div><div class="toc"><dl class="toc"><dt><span class="sect2"><a href="multibyte.html#MULTIBYTE-CHARSET-SUPPORTED">23.3.1. Supported Character Sets</a></span></dt><dt><span class="sect2"><a href="multibyte.html#id-1.6.10.5.6">23.3.2. Setting the Character Set</a></span></dt><dt><span class="sect2"><a href="multibyte.html#id-1.6.10.5.7">23.3.3. Automatic Character Set Conversion Between Server and Client</a></span></dt><dt><span class="sect2"><a href="multibyte.html#id-1.6.10.5.8">23.3.4. Further Reading</a></span></dt></dl></div><a id="id-1.6.10.5.2" class="indexterm"></a><p>
The character set support in <span class="productname">PostgreSQL</span>
allows you to store text in a variety of character sets (also called
encodings), including
single-byte character sets such as the ISO 8859 series and
multiple-byte character sets such as <acronym class="acronym">EUC</acronym> (Extended Unix
Code), UTF-8, and Mule internal code. All supported character sets
can be used transparently by clients, but a few are not supported
for use within the server (that is, as a server-side encoding).
The default character set is selected while
initializing your <span class="productname">PostgreSQL</span> database
cluster using <code class="command">initdb</code>. It can be overridden when you
create a database, so you can have multiple
databases each with a different character set.
</p><p>
An important restriction, however, is that each database's character set
must be compatible with the database's <code class="envar">LC_CTYPE</code> (character
classification) and <code class="envar">LC_COLLATE</code> (string sort order) locale
settings. For <code class="literal">C</code> or
<code class="literal">POSIX</code> locale, any character set is allowed, but for other
libc-provided locales there is only one character set that will work
correctly.
(On Windows, however, UTF-8 encoding can be used with any locale.)
If you have ICU support configured, ICU-provided locales can be used
with most but not all server-side encodings.
</p><div class="sect2" id="MULTIBYTE-CHARSET-SUPPORTED"><div class="titlepage"><div><div><h3 class="title">23.3.1. Supported Character Sets</h3></div></div></div><p>
<a class="xref" href="multibyte.html#CHARSET-TABLE" title="Table 23.1. PostgreSQL Character Sets">Table 23.1</a> shows the character sets available
for use in <span class="productname">PostgreSQL</span>.
</p><div class="table" id="CHARSET-TABLE"><p class="title"><strong>Table 23.1. <span class="productname">PostgreSQL</span> Character Sets</strong></p><div class="table-contents"><table class="table" summary="PostgreSQL Character Sets" border="1"><colgroup><col /><col /><col /><col /><col /><col /><col /></colgroup><thead><tr><th>Name</th><th>Description</th><th>Language</th><th>Server?</th><th>ICU?</th><th>Bytes/Char</th><th>Aliases</th></tr></thead><tbody><tr><td><code class="literal">BIG5</code></td><td>Big Five</td><td>Traditional Chinese</td><td>No</td><td>No</td><td>1-2</td><td><code class="literal">WIN950</code>, <code class="literal">Windows950</code></td></tr><tr><td><code class="literal">EUC_CN</code></td><td>Extended UNIX Code-CN</td><td>Simplified Chinese</td><td>Yes</td><td>Yes</td><td>1-3</td><td> </td></tr><tr><td><code class="literal">EUC_JP</code></td><td>Extended UNIX Code-JP</td><td>Japanese</td><td>Yes</td><td>Yes</td><td>1-3</td><td> </td></tr><tr><td><code class="literal">EUC_JIS_2004</code></td><td>Extended UNIX Code-JP, JIS X 0213</td><td>Japanese</td><td>Yes</td><td>No</td><td>1-3</td><td> </td></tr><tr><td><code class="literal">EUC_KR</code></td><td>Extended UNIX Code-KR</td><td>Korean</td><td>Yes</td><td>Yes</td><td>1-3</td><td> </td></tr><tr><td><code class="literal">EUC_TW</code></td><td>Extended UNIX Code-TW</td><td>Traditional Chinese, Taiwanese</td><td>Yes</td><td>Yes</td><td>1-3</td><td> </td></tr><tr><td><code class="literal">GB18030</code></td><td>National Standard</td><td>Chinese</td><td>No</td><td>No</td><td>1-4</td><td> </td></tr><tr><td><code class="literal">GBK</code></td><td>Extended National Standard</td><td>Simplified Chinese</td><td>No</td><td>No</td><td>1-2</td><td><code class="literal">WIN936</code>, <code class="literal">Windows936</code></td></tr><tr><td><code class="literal">ISO_8859_5</code></td><td>ISO 8859-5, <acronym class="acronym">ECMA</acronym> 113</td><td>Latin/Cyrillic</td><td>Yes</td><td>Yes</td><td>1</td><td> </td></tr><tr><td><code class="literal">ISO_8859_6</code></td><td>ISO 8859-6, <acronym class="acronym">ECMA</acronym> 114</td><td>Latin/Arabic</td><td>Yes</td><td>Yes</td><td>1</td><td> </td></tr><tr><td><code class="literal">ISO_8859_7</code></td><td>ISO 8859-7, <acronym class="acronym">ECMA</acronym> 118</td><td>Latin/Greek</td><td>Yes</td><td>Yes</td><td>1</td><td> </td></tr><tr><td><code class="literal">ISO_8859_8</code></td><td>ISO 8859-8, <acronym class="acronym">ECMA</acronym> 121</td><td>Latin/Hebrew</td><td>Yes</td><td>Yes</td><td>1</td><td> </td></tr><tr><td><code class="literal">JOHAB</code></td><td><acronym class="acronym">JOHAB</acronym></td><td>Korean (Hangul)</td><td>No</td><td>No</td><td>1-3</td><td> </td></tr><tr><td><code class="literal">KOI8R</code></td><td><acronym class="acronym">KOI</acronym>8-R</td><td>Cyrillic (Russian)</td><td>Yes</td><td>Yes</td><td>1</td><td><code class="literal">KOI8</code></td></tr><tr><td><code class="literal">KOI8U</code></td><td><acronym class="acronym">KOI</acronym>8-U</td><td>Cyrillic (Ukrainian)</td><td>Yes</td><td>Yes</td><td>1</td><td> </td></tr><tr><td><code class="literal">LATIN1</code></td><td>ISO 8859-1, <acronym class="acronym">ECMA</acronym> 94</td><td>Western European</td><td>Yes</td><td>Yes</td><td>1</td><td><code class="literal">ISO88591</code></td></tr><tr><td><code class="literal">LATIN2</code></td><td>ISO 8859-2, <acronym class="acronym">ECMA</acronym> 94</td><td>Central European</td><td>Yes</td><td>Yes</td><td>1</td><td><code class="literal">ISO88592</code></td></tr><tr><td><code class="literal">LATIN3</code></td><td>ISO 8859-3, <acronym class="acronym">ECMA</acronym> 94</td><td>South European</td><td>Yes</td><td>Yes</td><td>1</td><td><code class="literal">ISO88593</code></td></tr><tr><td><code class="literal">LATIN4</code></td><td>ISO 8859-4, <acronym class="acronym">ECMA</acronym> 94</td><td>North European</td><td>Yes</td><td>Yes</td><td>1</td><td><code class="literal">ISO88594</code></td></tr><tr><td><code class="literal">LATIN5</code></td><td>ISO 8859-9, <acronym class="acronym">ECMA</acronym> 128</td><td>Turkish</td><td>Yes</td><td>Yes</td><td>1</td><td><code class="literal">ISO88599</code></td></tr><tr><td><code class="literal">LATIN6</code></td><td>ISO 8859-10, <acronym class="acronym">ECMA</acronym> 144</td><td>Nordic</td><td>Yes</td><td>Yes</td><td>1</td><td><code class="literal">ISO885910</code></td></tr><tr><td><code class="literal">LATIN7</code></td><td>ISO 8859-13</td><td>Baltic</td><td>Yes</td><td>Yes</td><td>1</td><td><code class="literal">ISO885913</code></td></tr><tr><td><code class="literal">LATIN8</code></td><td>ISO 8859-14</td><td>Celtic</td><td>Yes</td><td>Yes</td><td>1</td><td><code class="literal">ISO885914</code></td></tr><tr><td><code class="literal">LATIN9</code></td><td>ISO 8859-15</td><td>LATIN1 with Euro and accents</td><td>Yes</td><td>Yes</td><td>1</td><td><code class="literal">ISO885915</code></td></tr><tr><td><code class="literal">LATIN10</code></td><td>ISO 8859-16, <acronym class="acronym">ASRO</acronym> SR 14111</td><td>Romanian</td><td>Yes</td><td>No</td><td>1</td><td><code class="literal">ISO885916</code></td></tr><tr><td><code class="literal">MULE_INTERNAL</code></td><td>Mule internal code</td><td>Multilingual Emacs</td><td>Yes</td><td>No</td><td>1-4</td><td> </td></tr><tr><td><code class="literal">SJIS</code></td><td>Shift JIS</td><td>Japanese</td><td>No</td><td>No</td><td>1-2</td><td><code class="literal">Mskanji</code>, <code class="literal">ShiftJIS</code>, <code class="literal">WIN932</code>, <code class="literal">Windows932</code></td></tr><tr><td><code class="literal">SHIFT_JIS_2004</code></td><td>Shift JIS, JIS X 0213</td><td>Japanese</td><td>No</td><td>No</td><td>1-2</td><td> </td></tr><tr><td><code class="literal">SQL_ASCII</code></td><td>unspecified (see text)</td><td><span class="emphasis"><em>any</em></span></td><td>Yes</td><td>No</td><td>1</td><td> </td></tr><tr><td><code class="literal">UHC</code></td><td>Unified Hangul Code</td><td>Korean</td><td>No</td><td>No</td><td>1-2</td><td><code class="literal">WIN949</code>, <code class="literal">Windows949</code></td></tr><tr><td><code class="literal">UTF8</code></td><td>Unicode, 8-bit</td><td><span class="emphasis"><em>all</em></span></td><td>Yes</td><td>Yes</td><td>1-4</td><td><code class="literal">Unicode</code></td></tr><tr><td><code class="literal">WIN866</code></td><td>Windows CP866</td><td>Cyrillic</td><td>Yes</td><td>Yes</td><td>1</td><td><code class="literal">ALT</code></td></tr><tr><td><code class="literal">WIN874</code></td><td>Windows CP874</td><td>Thai</td><td>Yes</td><td>No</td><td>1</td><td> </td></tr><tr><td><code class="literal">WIN1250</code></td><td>Windows CP1250</td><td>Central European</td><td>Yes</td><td>Yes</td><td>1</td><td> </td></tr><tr><td><code class="literal">WIN1251</code></td><td>Windows CP1251</td><td>Cyrillic</td><td>Yes</td><td>Yes</td><td>1</td><td><code class="literal">WIN</code></td></tr><tr><td><code class="literal">WIN1252</code></td><td>Windows CP1252</td><td>Western European</td><td>Yes</td><td>Yes</td><td>1</td><td> </td></tr><tr><td><code class="literal">WIN1253</code></td><td>Windows CP1253</td><td>Greek</td><td>Yes</td><td>Yes</td><td>1</td><td> </td></tr><tr><td><code class="literal">WIN1254</code></td><td>Windows CP1254</td><td>Turkish</td><td>Yes</td><td>Yes</td><td>1</td><td> </td></tr><tr><td><code class="literal">WIN1255</code></td><td>Windows CP1255</td><td>Hebrew</td><td>Yes</td><td>Yes</td><td>1</td><td> </td></tr><tr><td><code class="literal">WIN1256</code></td><td>Windows CP1256</td><td>Arabic</td><td>Yes</td><td>Yes</td><td>1</td><td> </td></tr><tr><td><code class="literal">WIN1257</code></td><td>Windows CP1257</td><td>Baltic</td><td>Yes</td><td>Yes</td><td>1</td><td> </td></tr><tr><td><code class="literal">WIN1258</code></td><td>Windows CP1258</td><td>Vietnamese</td><td>Yes</td><td>Yes</td><td>1</td><td><code class="literal">ABC</code>, <code class="literal">TCVN</code>, <code class="literal">TCVN5712</code>, <code class="literal">VSCII</code></td></tr></tbody></table></div></div><br class="table-break" /><p>
Not all client <acronym class="acronym">API</acronym>s support all the listed character sets. For example, the
<span class="productname">PostgreSQL</span>
JDBC driver does not support <code class="literal">MULE_INTERNAL</code>, <code class="literal">LATIN6</code>,
<code class="literal">LATIN8</code>, and <code class="literal">LATIN10</code>.
</p><p>
The <code class="literal">SQL_ASCII</code> setting behaves considerably differently
from the other settings. When the server character set is
<code class="literal">SQL_ASCII</code>, the server interprets byte values 0-127
according to the ASCII standard, while byte values 128-255 are taken
as uninterpreted characters. No encoding conversion will be done when
the setting is <code class="literal">SQL_ASCII</code>. Thus, this setting is not so
much a declaration that a specific encoding is in use, as a declaration
of ignorance about the encoding. In most cases, if you are
working with any non-ASCII data, it is unwise to use the
<code class="literal">SQL_ASCII</code> setting because
<span class="productname">PostgreSQL</span> will be unable to help you by
converting or validating non-ASCII characters.
</p></div><div class="sect2" id="id-1.6.10.5.6"><div class="titlepage"><div><div><h3 class="title">23.3.2. Setting the Character Set</h3></div></div></div><p>
<code class="command">initdb</code> defines the default character set (encoding)
for a <span class="productname">PostgreSQL</span> cluster. For example,
</p><pre class="screen">
initdb -E EUC_JP
</pre><p>
sets the default character set to
<code class="literal">EUC_JP</code> (Extended Unix Code for Japanese). You
can use <code class="option">--encoding</code> instead of
<code class="option">-E</code> if you prefer longer option strings.
If no <code class="option">-E</code> or <code class="option">--encoding</code> option is
given, <code class="command">initdb</code> attempts to determine the appropriate
encoding to use based on the specified or default locale.
</p><p>
You can specify a non-default encoding at database creation time,
provided that the encoding is compatible with the selected locale:
</p><pre class="screen">
createdb -E EUC_KR -T template0 --lc-collate=ko_KR.euckr --lc-ctype=ko_KR.euckr korean
</pre><p>
This will create a database named <code class="literal">korean</code> that
uses the character set <code class="literal">EUC_KR</code>, and locale <code class="literal">ko_KR</code>.
Another way to accomplish this is to use this SQL command:
</p><pre class="programlisting">
CREATE DATABASE korean WITH ENCODING 'EUC_KR' LC_COLLATE='ko_KR.euckr' LC_CTYPE='ko_KR.euckr' TEMPLATE=template0;
</pre><p>
Notice that the above commands specify copying the <code class="literal">template0</code>
database. When copying any other database, the encoding and locale
settings cannot be changed from those of the source database, because
that might result in corrupt data. For more information see
<a class="xref" href="manage-ag-templatedbs.html" title="22.3. Template Databases">Section 22.3</a>.
</p><p>
The encoding for a database is stored in the system catalog
<code class="literal">pg_database</code>. You can see it by using the
<code class="command">psql</code> <code class="option">-l</code> option or the
<code class="command">\l</code> command.
</p><pre class="screen">
$ <strong class="userinput"><code>psql -l</code></strong>
List of databases
Name | Owner | Encoding | Collation | Ctype | Access Privileges
-----------+----------+-----------+-------------+-------------+-------------------------------------
clocaledb | hlinnaka | SQL_ASCII | C | C |
englishdb | hlinnaka | UTF8 | en_GB.UTF8 | en_GB.UTF8 |
japanese | hlinnaka | UTF8 | ja_JP.UTF8 | ja_JP.UTF8 |
korean | hlinnaka | EUC_KR | ko_KR.euckr | ko_KR.euckr |
postgres | hlinnaka | UTF8 | fi_FI.UTF8 | fi_FI.UTF8 |
template0 | hlinnaka | UTF8 | fi_FI.UTF8 | fi_FI.UTF8 | {=c/hlinnaka,hlinnaka=CTc/hlinnaka}
template1 | hlinnaka | UTF8 | fi_FI.UTF8 | fi_FI.UTF8 | {=c/hlinnaka,hlinnaka=CTc/hlinnaka}
(7 rows)
</pre><p>
</p><div class="important"><h3 class="title">Important</h3><p>
On most modern operating systems, <span class="productname">PostgreSQL</span>
can determine which character set is implied by the <code class="envar">LC_CTYPE</code>
setting, and it will enforce that only the matching database encoding is
used. On older systems it is your responsibility to ensure that you use
the encoding expected by the locale you have selected. A mistake in
this area is likely to lead to strange behavior of locale-dependent
operations such as sorting.
</p><p>
<span class="productname">PostgreSQL</span> will allow superusers to create
databases with <code class="literal">SQL_ASCII</code> encoding even when
<code class="envar">LC_CTYPE</code> is not <code class="literal">C</code> or <code class="literal">POSIX</code>. As noted
above, <code class="literal">SQL_ASCII</code> does not enforce that the data stored in
the database has any particular encoding, and so this choice poses risks
of locale-dependent misbehavior. Using this combination of settings is
deprecated and may someday be forbidden altogether.
</p></div></div><div class="sect2" id="id-1.6.10.5.7"><div class="titlepage"><div><div><h3 class="title">23.3.3. Automatic Character Set Conversion Between Server and Client</h3></div></div></div><p>
<span class="productname">PostgreSQL</span> supports automatic
character set conversion between server and client for certain
character set combinations. The conversion information is stored in the
<code class="literal">pg_conversion</code> system catalog. <span class="productname">PostgreSQL</span>
comes with some predefined conversions, as shown in <a class="xref" href="multibyte.html#MULTIBYTE-TRANSLATION-TABLE" title="Table 23.2. Client/Server Character Set Conversions">Table 23.2</a>. You can create a new
conversion using the SQL command <code class="command">CREATE CONVERSION</code>.
</p><div class="table" id="MULTIBYTE-TRANSLATION-TABLE"><p class="title"><strong>Table 23.2. Client/Server Character Set Conversions</strong></p><div class="table-contents"><table class="table" summary="Client/Server Character Set Conversions" border="1"><colgroup><col /><col /></colgroup><thead><tr><th>Server Character Set</th><th>Available Client Character Sets</th></tr></thead><tbody><tr><td><code class="literal">BIG5</code></td><td><span class="emphasis"><em>not supported as a server encoding</em></span>
</td></tr><tr><td><code class="literal">EUC_CN</code></td><td><span class="emphasis"><em>EUC_CN</em></span>,
<code class="literal">MULE_INTERNAL</code>,
<code class="literal">UTF8</code>
</td></tr><tr><td><code class="literal">EUC_JP</code></td><td><span class="emphasis"><em>EUC_JP</em></span>,
<code class="literal">MULE_INTERNAL</code>,
<code class="literal">SJIS</code>,
<code class="literal">UTF8</code>
</td></tr><tr><td><code class="literal">EUC_JIS_2004</code></td><td><span class="emphasis"><em>EUC_JIS_2004</em></span>,
<code class="literal">SHIFT_JIS_2004</code>,
<code class="literal">UTF8</code>
</td></tr><tr><td><code class="literal">EUC_KR</code></td><td><span class="emphasis"><em>EUC_KR</em></span>,
<code class="literal">MULE_INTERNAL</code>,
<code class="literal">UTF8</code>
</td></tr><tr><td><code class="literal">EUC_TW</code></td><td><span class="emphasis"><em>EUC_TW</em></span>,
<code class="literal">BIG5</code>,
<code class="literal">MULE_INTERNAL</code>,
<code class="literal">UTF8</code>
</td></tr><tr><td><code class="literal">GB18030</code></td><td><span class="emphasis"><em>not supported as a server encoding</em></span>
</td></tr><tr><td><code class="literal">GBK</code></td><td><span class="emphasis"><em>not supported as a server encoding</em></span>
</td></tr><tr><td><code class="literal">ISO_8859_5</code></td><td><span class="emphasis"><em>ISO_8859_5</em></span>,
<code class="literal">KOI8R</code>,
<code class="literal">MULE_INTERNAL</code>,
<code class="literal">UTF8</code>,
<code class="literal">WIN866</code>,
<code class="literal">WIN1251</code>
</td></tr><tr><td><code class="literal">ISO_8859_6</code></td><td><span class="emphasis"><em>ISO_8859_6</em></span>,
<code class="literal">UTF8</code>
</td></tr><tr><td><code class="literal">ISO_8859_7</code></td><td><span class="emphasis"><em>ISO_8859_7</em></span>,
<code class="literal">UTF8</code>
</td></tr><tr><td><code class="literal">ISO_8859_8</code></td><td><span class="emphasis"><em>ISO_8859_8</em></span>,
<code class="literal">UTF8</code>
</td></tr><tr><td><code class="literal">JOHAB</code></td><td><span class="emphasis"><em>not supported as a server encoding</em></span>
</td></tr><tr><td><code class="literal">KOI8R</code></td><td><span class="emphasis"><em>KOI8R</em></span>,
<code class="literal">ISO_8859_5</code>,
<code class="literal">MULE_INTERNAL</code>,
<code class="literal">UTF8</code>,
<code class="literal">WIN866</code>,
<code class="literal">WIN1251</code>
</td></tr><tr><td><code class="literal">KOI8U</code></td><td><span class="emphasis"><em>KOI8U</em></span>,
<code class="literal">UTF8</code>
</td></tr><tr><td><code class="literal">LATIN1</code></td><td><span class="emphasis"><em>LATIN1</em></span>,
<code class="literal">MULE_INTERNAL</code>,
<code class="literal">UTF8</code>
</td></tr><tr><td><code class="literal">LATIN2</code></td><td><span class="emphasis"><em>LATIN2</em></span>,
<code class="literal">MULE_INTERNAL</code>,
<code class="literal">UTF8</code>,
<code class="literal">WIN1250</code>
</td></tr><tr><td><code class="literal">LATIN3</code></td><td><span class="emphasis"><em>LATIN3</em></span>,
<code class="literal">MULE_INTERNAL</code>,
<code class="literal">UTF8</code>
</td></tr><tr><td><code class="literal">LATIN4</code></td><td><span class="emphasis"><em>LATIN4</em></span>,
<code class="literal">MULE_INTERNAL</code>,
<code class="literal">UTF8</code>
</td></tr><tr><td><code class="literal">LATIN5</code></td><td><span class="emphasis"><em>LATIN5</em></span>,
<code class="literal">UTF8</code>
</td></tr><tr><td><code class="literal">LATIN6</code></td><td><span class="emphasis"><em>LATIN6</em></span>,
<code class="literal">UTF8</code>
</td></tr><tr><td><code class="literal">LATIN7</code></td><td><span class="emphasis"><em>LATIN7</em></span>,
<code class="literal">UTF8</code>
</td></tr><tr><td><code class="literal">LATIN8</code></td><td><span class="emphasis"><em>LATIN8</em></span>,
<code class="literal">UTF8</code>
</td></tr><tr><td><code class="literal">LATIN9</code></td><td><span class="emphasis"><em>LATIN9</em></span>,
<code class="literal">UTF8</code>
</td></tr><tr><td><code class="literal">LATIN10</code></td><td><span class="emphasis"><em>LATIN10</em></span>,
<code class="literal">UTF8</code>
</td></tr><tr><td><code class="literal">MULE_INTERNAL</code></td><td><span class="emphasis"><em>MULE_INTERNAL</em></span>,
<code class="literal">BIG5</code>,
<code class="literal">EUC_CN</code>,
<code class="literal">EUC_JP</code>,
<code class="literal">EUC_KR</code>,
<code class="literal">EUC_TW</code>,
<code class="literal">ISO_8859_5</code>,
<code class="literal">KOI8R</code>,
<code class="literal">LATIN1</code> to <code class="literal">LATIN4</code>,
<code class="literal">SJIS</code>,
<code class="literal">WIN866</code>,
<code class="literal">WIN1250</code>,
<code class="literal">WIN1251</code>
</td></tr><tr><td><code class="literal">SJIS</code></td><td><span class="emphasis"><em>not supported as a server encoding</em></span>
</td></tr><tr><td><code class="literal">SHIFT_JIS_2004</code></td><td><span class="emphasis"><em>not supported as a server encoding</em></span>
</td></tr><tr><td><code class="literal">SQL_ASCII</code></td><td><span class="emphasis"><em>any (no conversion will be performed)</em></span>
</td></tr><tr><td><code class="literal">UHC</code></td><td><span class="emphasis"><em>not supported as a server encoding</em></span>
</td></tr><tr><td><code class="literal">UTF8</code></td><td><span class="emphasis"><em>all supported encodings</em></span>
</td></tr><tr><td><code class="literal">WIN866</code></td><td><span class="emphasis"><em>WIN866</em></span>,
<code class="literal">ISO_8859_5</code>,
<code class="literal">KOI8R</code>,
<code class="literal">MULE_INTERNAL</code>,
<code class="literal">UTF8</code>,
<code class="literal">WIN1251</code>
</td></tr><tr><td><code class="literal">WIN874</code></td><td><span class="emphasis"><em>WIN874</em></span>,
<code class="literal">UTF8</code>
</td></tr><tr><td><code class="literal">WIN1250</code></td><td><span class="emphasis"><em>WIN1250</em></span>,
<code class="literal">LATIN2</code>,
<code class="literal">MULE_INTERNAL</code>,
<code class="literal">UTF8</code>
</td></tr><tr><td><code class="literal">WIN1251</code></td><td><span class="emphasis"><em>WIN1251</em></span>,
<code class="literal">ISO_8859_5</code>,
<code class="literal">KOI8R</code>,
<code class="literal">MULE_INTERNAL</code>,
<code class="literal">UTF8</code>,
<code class="literal">WIN866</code>
</td></tr><tr><td><code class="literal">WIN1252</code></td><td><span class="emphasis"><em>WIN1252</em></span>,
<code class="literal">UTF8</code>
</td></tr><tr><td><code class="literal">WIN1253</code></td><td><span class="emphasis"><em>WIN1253</em></span>,
<code class="literal">UTF8</code>
</td></tr><tr><td><code class="literal">WIN1254</code></td><td><span class="emphasis"><em>WIN1254</em></span>,
<code class="literal">UTF8</code>
</td></tr><tr><td><code class="literal">WIN1255</code></td><td><span class="emphasis"><em>WIN1255</em></span>,
<code class="literal">UTF8</code>
</td></tr><tr><td><code class="literal">WIN1256</code></td><td><span class="emphasis"><em>WIN1256</em></span>,
<code class="literal">UTF8</code>
</td></tr><tr><td><code class="literal">WIN1257</code></td><td><span class="emphasis"><em>WIN1257</em></span>,
<code class="literal">UTF8</code>
</td></tr><tr><td><code class="literal">WIN1258</code></td><td><span class="emphasis"><em>WIN1258</em></span>,
<code class="literal">UTF8</code>
</td></tr></tbody></table></div></div><br class="table-break" /><p>
To enable automatic character set conversion, you have to
tell <span class="productname">PostgreSQL</span> the character set
(encoding) you would like to use in the client. There are several
ways to accomplish this:
</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>
Using the <code class="command">\encoding</code> command in
<span class="application">psql</span>.
<code class="command">\encoding</code> allows you to change client
encoding on the fly. For
example, to change the encoding to <code class="literal">SJIS</code>, type:
</p><pre class="programlisting">
\encoding SJIS
</pre><p>
</p></li><li class="listitem"><p>
<span class="application">libpq</span> (<a class="xref" href="libpq-control.html" title="34.10. Control Functions">Section 34.10</a>) has functions to control the client encoding.
</p></li><li class="listitem"><p>
Using <code class="command">SET client_encoding TO</code>.
Setting the client encoding can be done with this SQL command:
</p><pre class="programlisting">
SET CLIENT_ENCODING TO '<em class="replaceable"><code>value</code></em>';
</pre><p>
Also you can use the standard SQL syntax <code class="literal">SET NAMES</code>
for this purpose:
</p><pre class="programlisting">
SET NAMES '<em class="replaceable"><code>value</code></em>';
</pre><p>
To query the current client encoding:
</p><pre class="programlisting">
SHOW client_encoding;
</pre><p>
To return to the default encoding:
</p><pre class="programlisting">
RESET client_encoding;
</pre><p>
</p></li><li class="listitem"><p>
Using <code class="envar">PGCLIENTENCODING</code>. If the environment variable
<code class="envar">PGCLIENTENCODING</code> is defined in the client's
environment, that client encoding is automatically selected
when a connection to the server is made. (This can
subsequently be overridden using any of the other methods
mentioned above.)
</p></li><li class="listitem"><p>
Using the configuration variable <a class="xref" href="runtime-config-client.html#GUC-CLIENT-ENCODING">client_encoding</a>. If the
<code class="varname">client_encoding</code> variable is set, that client
encoding is automatically selected when a connection to the
server is made. (This can subsequently be overridden using any
of the other methods mentioned above.)
</p></li></ul></div><p>
</p><p>
If the conversion of a particular character is not possible
— suppose you chose <code class="literal">EUC_JP</code> for the
server and <code class="literal">LATIN1</code> for the client, and some
Japanese characters are returned that do not have a representation in
<code class="literal">LATIN1</code> — an error is reported.
</p><p>
If the client character set is defined as <code class="literal">SQL_ASCII</code>,
encoding conversion is disabled, regardless of the server's character
set. Just as for the server, use of <code class="literal">SQL_ASCII</code> is unwise
unless you are working with all-ASCII data.
</p></div><div class="sect2" id="id-1.6.10.5.8"><div class="titlepage"><div><div><h3 class="title">23.3.4. Further Reading</h3></div></div></div><p>
These are good sources to start learning about various kinds of encoding
systems.
</p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="citetitle">CJKV Information Processing: Chinese, Japanese, Korean & Vietnamese Computing</em></span></dt><dd><p>
Contains detailed explanations of <code class="literal">EUC_JP</code>,
<code class="literal">EUC_CN</code>, <code class="literal">EUC_KR</code>,
<code class="literal">EUC_TW</code>.
</p></dd><dt><span class="term"><a class="ulink" href="http://www.unicode.org/" target="_top">http://www.unicode.org/</a></span></dt><dd><p>
The web site of the Unicode Consortium.
</p></dd><dt><span class="term">RFC 3629</span></dt><dd><p>
<acronym class="acronym">UTF</acronym>-8 (8-bit UCS/Unicode Transformation
Format) is defined here.
</p></dd></dl></div><p>
</p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="collation.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="charset.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="maintenance.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">23.2. Collation Support </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 24. Routine Database Maintenance Tasks</td></tr></table></div></body></html>
