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postgresql8.3-docs-8.3.6-2mdv2008.1.x86_64.rpm

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CLASS="SECT1"
><H1
CLASS="SECT1"
><A
NAME="MULTIBYTE"
>22.2. Character Set Support</A
></H1
><A
NAME="AEN27030"
></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 <TT
CLASS="COMMAND"
>initdb</TT
>.  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 character set
   must be compatible with the server's <TT
CLASS="ENVAR"
>LC_CTYPE</TT
> setting.
   When <TT
CLASS="ENVAR"
>LC_CTYPE</TT
> is <TT
CLASS="LITERAL"
>C</TT
> or <TT
CLASS="LITERAL"
>POSIX</TT
>, any
   character set is allowed, but for other settings of <TT
CLASS="ENVAR"
>LC_CTYPE</TT
>
   there is only one character set that will work correctly.
   Since the <TT
CLASS="ENVAR"
>LC_CTYPE</TT
> setting is frozen by <TT
CLASS="COMMAND"
>initdb</TT
>, the
   apparent flexibility to use different encodings in different databases
   of a cluster is more theoretical than real, except when you select
   <TT
CLASS="LITERAL"
>C</TT
> or <TT
CLASS="LITERAL"
>POSIX</TT
> locale (thus disabling any real locale
   awareness).  It is likely that these mechanisms will be revisited in future
   versions of <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>.
  </P
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="MULTIBYTE-CHARSET-SUPPORTED"
>22.2.1. Supported Character Sets</A
></H2
><P
>     <A
HREF="multibyte.html#CHARSET-TABLE"
>Table 22-1</A
> shows the character sets available
     for use in <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>.
    </P
><DIV
CLASS="TABLE"
><A
NAME="CHARSET-TABLE"
></A
><P
><B
>Table 22-1. <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> Character Sets</B
></P
><TABLE
BORDER="1"
CLASS="CALSTABLE"
><COL><COL><COL><COL><COL><COL><THEAD
><TR
><TH
>Name</TH
><TH
>Description</TH
><TH
>Language</TH
><TH
>Server?</TH
><TH
>Bytes/Char</TH
><TH
>Aliases</TH
></TR
></THEAD
><TBODY
><TR
><TD
><TT
CLASS="LITERAL"
>BIG5</TT
></TD
><TD
>Big Five</TD
><TD
>Traditional Chinese</TD
><TD
>No</TD
><TD
>1-2</TD
><TD
><TT
CLASS="LITERAL"
>WIN950</TT
>, <TT
CLASS="LITERAL"
>Windows950</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>EUC_CN</TT
></TD
><TD
>Extended UNIX Code-CN</TD
><TD
>Simplified Chinese</TD
><TD
>Yes</TD
><TD
>1-3</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>EUC_JP</TT
></TD
><TD
>Extended UNIX Code-JP</TD
><TD
>Japanese</TD
><TD
>Yes</TD
><TD
>1-3</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>EUC_JIS_2004</TT
></TD
><TD
>Extended UNIX Code-JP, JIS X 0213</TD
><TD
>Japanese</TD
><TD
>Yes</TD
><TD
>1-3</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>EUC_KR</TT
></TD
><TD
>Extended UNIX Code-KR</TD
><TD
>Korean</TD
><TD
>Yes</TD
><TD
>1-3</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>EUC_TW</TT
></TD
><TD
>Extended UNIX Code-TW</TD
><TD
>Traditional Chinese, Taiwanese</TD
><TD
>Yes</TD
><TD
>1-3</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>GB18030</TT
></TD
><TD
>National Standard</TD
><TD
>Chinese</TD
><TD
>No</TD
><TD
>1-2</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>GBK</TT
></TD
><TD
>Extended National Standard</TD
><TD
>Simplified Chinese</TD
><TD
>No</TD
><TD
>1-2</TD
><TD
><TT
CLASS="LITERAL"
>WIN936</TT
>, <TT
CLASS="LITERAL"
>Windows936</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>ISO_8859_5</TT
></TD
><TD
>ISO 8859-5, <ACRONYM
CLASS="ACRONYM"
>ECMA</ACRONYM
> 113</TD
><TD
>Latin/Cyrillic</TD
><TD
>Yes</TD
><TD
>1</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>ISO_8859_6</TT
></TD
><TD
>ISO 8859-6, <ACRONYM
CLASS="ACRONYM"
>ECMA</ACRONYM
> 114</TD
><TD
>Latin/Arabic</TD
><TD
>Yes</TD
><TD
>1</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>ISO_8859_7</TT
></TD
><TD
>ISO 8859-7, <ACRONYM
CLASS="ACRONYM"
>ECMA</ACRONYM
> 118</TD
><TD
>Latin/Greek</TD
><TD
>Yes</TD
><TD
>1</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>ISO_8859_8</TT
></TD
><TD
>ISO 8859-8, <ACRONYM
CLASS="ACRONYM"
>ECMA</ACRONYM
> 121</TD
><TD
>Latin/Hebrew</TD
><TD
>Yes</TD
><TD
>1</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>JOHAB</TT
></TD
><TD
><ACRONYM
CLASS="ACRONYM"
>JOHAB</ACRONYM
></TD
><TD
>Korean (Hangul)</TD
><TD
>No</TD
><TD
>1-3</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>KOI8</TT
></TD
><TD
><ACRONYM
CLASS="ACRONYM"
>KOI</ACRONYM
>8-R(U)</TD
><TD
>Cyrillic</TD
><TD
>Yes</TD
><TD
>1</TD
><TD
><TT
CLASS="LITERAL"
>KOI8R</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>LATIN1</TT
></TD
><TD
>ISO 8859-1, <ACRONYM
CLASS="ACRONYM"
>ECMA</ACRONYM
> 94</TD
><TD
>Western European</TD
><TD
>Yes</TD
><TD
>1</TD
><TD
><TT
CLASS="LITERAL"
>ISO88591</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>LATIN2</TT
></TD
><TD
>ISO 8859-2, <ACRONYM
CLASS="ACRONYM"
>ECMA</ACRONYM
> 94</TD
><TD
>Central European</TD
><TD
>Yes</TD
><TD
>1</TD
><TD
><TT
CLASS="LITERAL"
>ISO88592</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>LATIN3</TT
></TD
><TD
>ISO 8859-3, <ACRONYM
CLASS="ACRONYM"
>ECMA</ACRONYM
> 94</TD
><TD
>South European</TD
><TD
>Yes</TD
><TD
>1</TD
><TD
><TT
CLASS="LITERAL"
>ISO88593</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>LATIN4</TT
></TD
><TD
>ISO 8859-4, <ACRONYM
CLASS="ACRONYM"
>ECMA</ACRONYM
> 94</TD
><TD
>North European</TD
><TD
>Yes</TD
><TD
>1</TD
><TD
><TT
CLASS="LITERAL"
>ISO88594</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>LATIN5</TT
></TD
><TD
>ISO 8859-9, <ACRONYM
CLASS="ACRONYM"
>ECMA</ACRONYM
> 128</TD
><TD
>Turkish</TD
><TD
>Yes</TD
><TD
>1</TD
><TD
><TT
CLASS="LITERAL"
>ISO88599</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>LATIN6</TT
></TD
><TD
>ISO 8859-10, <ACRONYM
CLASS="ACRONYM"
>ECMA</ACRONYM
> 144</TD
><TD
>Nordic</TD
><TD
>Yes</TD
><TD
>1</TD
><TD
><TT
CLASS="LITERAL"
>ISO885910</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>LATIN7</TT
></TD
><TD
>ISO 8859-13</TD
><TD
>Baltic</TD
><TD
>Yes</TD
><TD
>1</TD
><TD
><TT
CLASS="LITERAL"
>ISO885913</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>LATIN8</TT
></TD
><TD
>ISO 8859-14</TD
><TD
>Celtic</TD
><TD
>Yes</TD
><TD
>1</TD
><TD
><TT
CLASS="LITERAL"
>ISO885914</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>LATIN9</TT
></TD
><TD
>ISO 8859-15</TD
><TD
>LATIN1 with Euro and accents</TD
><TD
>Yes</TD
><TD
>1</TD
><TD
>ISO885915</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>LATIN10</TT
></TD
><TD
>ISO 8859-16, <ACRONYM
CLASS="ACRONYM"
>ASRO</ACRONYM
> SR 14111</TD
><TD
>Romanian</TD
><TD
>Yes</TD
><TD
>1</TD
><TD
><TT
CLASS="LITERAL"
>ISO885916</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>MULE_INTERNAL</TT
></TD
><TD
>Mule internal code</TD
><TD
>Multilingual Emacs</TD
><TD
>Yes</TD
><TD
>1-4</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>SJIS</TT
></TD
><TD
>Shift JIS</TD
><TD
>Japanese</TD
><TD
>No</TD
><TD
>1-2</TD
><TD
><TT
CLASS="LITERAL"
>Mskanji</TT
>, <TT
CLASS="LITERAL"
>ShiftJIS</TT
>, <TT
CLASS="LITERAL"
>WIN932</TT
>, <TT
CLASS="LITERAL"
>Windows932</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>SHIFT_JIS_2004</TT
></TD
><TD
>Shift JIS, JIS X 0213</TD
><TD
>Japanese</TD
><TD
>No</TD
><TD
>1-2</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>SQL_ASCII</TT
></TD
><TD
>unspecified (see text)</TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>any</I
></SPAN
></TD
><TD
>Yes</TD
><TD
>1</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>UHC</TT
></TD
><TD
>Unified Hangul Code</TD
><TD
>Korean</TD
><TD
>No</TD
><TD
>1-2</TD
><TD
><TT
CLASS="LITERAL"
>WIN949</TT
>, <TT
CLASS="LITERAL"
>Windows949</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>UTF8</TT
></TD
><TD
>Unicode, 8-bit</TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>all</I
></SPAN
></TD
><TD
>Yes</TD
><TD
>1-4</TD
><TD
><TT
CLASS="LITERAL"
>Unicode</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>WIN866</TT
></TD
><TD
>Windows CP866</TD
><TD
>Cyrillic</TD
><TD
>Yes</TD
><TD
>1</TD
><TD
><TT
CLASS="LITERAL"
>ALT</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>WIN874</TT
></TD
><TD
>Windows CP874</TD
><TD
>Thai</TD
><TD
>Yes</TD
><TD
>1</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>WIN1250</TT
></TD
><TD
>Windows CP1250</TD
><TD
>Central European</TD
><TD
>Yes</TD
><TD
>1</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>WIN1251</TT
></TD
><TD
>Windows CP1251</TD
><TD
>Cyrillic</TD
><TD
>Yes</TD
><TD
>1</TD
><TD
><TT
CLASS="LITERAL"
>WIN</TT
></TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>WIN1252</TT
></TD
><TD
>Windows CP1252</TD
><TD
>Western European</TD
><TD
>Yes</TD
><TD
>1</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>WIN1253</TT
></TD
><TD
>Windows CP1253</TD
><TD
>Greek</TD
><TD
>Yes</TD
><TD
>1</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>WIN1254</TT
></TD
><TD
>Windows CP1254</TD
><TD
>Turkish</TD
><TD
>Yes</TD
><TD
>1</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>WIN1255</TT
></TD
><TD
>Windows CP1255</TD
><TD
>Hebrew</TD
><TD
>Yes</TD
><TD
>1</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>WIN1256</TT
></TD
><TD
>Windows CP1256</TD
><TD
>Arabic</TD
><TD
>Yes</TD
><TD
>1</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>WIN1257</TT
></TD
><TD
>Windows CP1257</TD
><TD
>Baltic</TD
><TD
>Yes</TD
><TD
>1</TD
><TD
>&nbsp;</TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>WIN1258</TT
></TD
><TD
>Windows CP1258</TD
><TD
>Vietnamese</TD
><TD
>Yes</TD
><TD
>1</TD
><TD
><TT
CLASS="LITERAL"
>ABC</TT
>, <TT
CLASS="LITERAL"
>TCVN</TT
>, <TT
CLASS="LITERAL"
>TCVN5712</TT
>, <TT
CLASS="LITERAL"
>VSCII</TT
></TD
></TR
></TBODY
></TABLE
></DIV
><P
>      Not all <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 <TT
CLASS="LITERAL"
>MULE_INTERNAL</TT
>, <TT
CLASS="LITERAL"
>LATIN6</TT
>,
      <TT
CLASS="LITERAL"
>LATIN8</TT
>, and <TT
CLASS="LITERAL"
>LATIN10</TT
>.
     </P
><P
>      The <TT
CLASS="LITERAL"
>SQL_ASCII</TT
> setting behaves considerably differently
      from the other settings.  When the server character set is
      <TT
CLASS="LITERAL"
>SQL_ASCII</TT
>, 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 <TT
CLASS="LITERAL"
>SQL_ASCII</TT
>.  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
      <TT
CLASS="LITERAL"
>SQL_ASCII</TT
> 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"
><H2
CLASS="SECT2"
><A
NAME="AEN27449"
>22.2.2. Setting the Character Set</A
></H2
><P
>     <TT
CLASS="COMMAND"
>initdb</TT
> defines the default character set
     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 (encoding) to
     <TT
CLASS="LITERAL"
>EUC_JP</TT
> (Extended Unix Code for Japanese).  You
     can use <TT
CLASS="OPTION"
>--encoding</TT
> instead of
     <TT
CLASS="OPTION"
>-E</TT
> if you prefer to type longer option strings.
     If no <TT
CLASS="OPTION"
>-E</TT
> or <TT
CLASS="OPTION"
>--encoding</TT
> option is
     given, <TT
CLASS="COMMAND"
>initdb</TT
> attempts to determine the appropriate
     encoding to use based on the specified or default locale.
    </P
><P
>     If you have selected <TT
CLASS="LITERAL"
>C</TT
> or <TT
CLASS="LITERAL"
>POSIX</TT
> locale,
     you can create a database with a different character set:

</P><PRE
CLASS="SCREEN"
>createdb -E EUC_KR korean</PRE
><P>

     This will create a database named <TT
CLASS="LITERAL"
>korean</TT
> that
     uses the character set <TT
CLASS="LITERAL"
>EUC_KR</TT
>.  Another way to
     accomplish this is to use this SQL command:

</P><PRE
CLASS="PROGRAMLISTING"
>CREATE DATABASE korean WITH ENCODING 'EUC_KR';</PRE
><P>

     The encoding for a database is stored in the system catalog
     <TT
CLASS="LITERAL"
>pg_database</TT
>.  You can see it by using the
     <TT
CLASS="OPTION"
>-l</TT
> option or the <TT
CLASS="COMMAND"
>\l</TT
> command
     of <TT
CLASS="COMMAND"
>psql</TT
>.

</P><PRE
CLASS="SCREEN"
>$ <KBD
CLASS="USERINPUT"
>psql -l</KBD
>
            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)</PRE
><P>
    </P
><DIV
CLASS="IMPORTANT"
><BLOCKQUOTE
CLASS="IMPORTANT"
><P
><B
>Important: </B
>      On most modern operating systems, <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>
      can determine which character set is implied by an <TT
CLASS="ENVAR"
>LC_CTYPE</TT
>
      setting, and it will enforce that only the correct 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 misbehavior of locale-dependent
      operations such as sorting.
     </P
><P
>      <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> will allow superusers to create
      databases with <TT
CLASS="LITERAL"
>SQL_ASCII</TT
> encoding even when
      <TT
CLASS="ENVAR"
>LC_CTYPE</TT
> is not <TT
CLASS="LITERAL"
>C</TT
> or <TT
CLASS="LITERAL"
>POSIX</TT
>.  As noted
      above, <TT
CLASS="LITERAL"
>SQL_ASCII</TT
> 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
></BLOCKQUOTE
></DIV
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN27485"
>22.2.3. Automatic Character Set Conversion Between Server and Client</A
></H2
><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
     <TT
CLASS="LITERAL"
>pg_conversion</TT
> system catalog.  <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>
     comes with some predefined conversions, as shown in <A
HREF="multibyte.html#MULTIBYTE-TRANSLATION-TABLE"
>Table 22-2</A
>. You can create a new
     conversion using the SQL command <TT
CLASS="COMMAND"
>CREATE CONVERSION</TT
>.
    </P
><DIV
CLASS="TABLE"
><A
NAME="MULTIBYTE-TRANSLATION-TABLE"
></A
><P
><B
>Table 22-2. Client/Server Character Set Conversions</B
></P
><TABLE
BORDER="1"
CLASS="CALSTABLE"
><COL><COL><THEAD
><TR
><TH
>Server Character Set</TH
><TH
>Available Client Character Sets</TH
></TR
></THEAD
><TBODY
><TR
><TD
><TT
CLASS="LITERAL"
>BIG5</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>not supported as a server encoding</I
></SPAN
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>EUC_CN</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>EUC_CN</I
></SPAN
>,
         <TT
CLASS="LITERAL"
>MULE_INTERNAL</TT
>,
         <TT
CLASS="LITERAL"
>UTF8</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>EUC_JP</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>EUC_JP</I
></SPAN
>,
         <TT
CLASS="LITERAL"
>MULE_INTERNAL</TT
>,
         <TT
CLASS="LITERAL"
>SJIS</TT
>,
         <TT
CLASS="LITERAL"
>UTF8</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>EUC_KR</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>EUC_KR</I
></SPAN
>,
         <TT
CLASS="LITERAL"
>MULE_INTERNAL</TT
>,
         <TT
CLASS="LITERAL"
>UTF8</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>EUC_TW</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>EUC_TW</I
></SPAN
>,
         <TT
CLASS="LITERAL"
>BIG5</TT
>,
         <TT
CLASS="LITERAL"
>MULE_INTERNAL</TT
>,
         <TT
CLASS="LITERAL"
>UTF8</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>GB18030</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>not supported as a server encoding</I
></SPAN
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>GBK</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>not supported as a server encoding</I
></SPAN
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>ISO_8859_5</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>ISO_8859_5</I
></SPAN
>,
         <TT
CLASS="LITERAL"
>KOI8</TT
>,
         <TT
CLASS="LITERAL"
>MULE_INTERNAL</TT
>,
         <TT
CLASS="LITERAL"
>UTF8</TT
>,
         <TT
CLASS="LITERAL"
>WIN866</TT
>,
         <TT
CLASS="LITERAL"
>WIN1251</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>ISO_8859_6</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>ISO_8859_6</I
></SPAN
>,
         <TT
CLASS="LITERAL"
>UTF8</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>ISO_8859_7</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>ISO_8859_7</I
></SPAN
>,
         <TT
CLASS="LITERAL"
>UTF8</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>ISO_8859_8</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>ISO_8859_8</I
></SPAN
>,
         <TT
CLASS="LITERAL"
>UTF8</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>JOHAB</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>JOHAB</I
></SPAN
>,
         <TT
CLASS="LITERAL"
>UTF8</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>KOI8</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>KOI8</I
></SPAN
>,
         <TT
CLASS="LITERAL"
>ISO_8859_5</TT
>,
         <TT
CLASS="LITERAL"
>MULE_INTERNAL</TT
>,
         <TT
CLASS="LITERAL"
>UTF8</TT
>,
         <TT
CLASS="LITERAL"
>WIN866</TT
>,
         <TT
CLASS="LITERAL"
>WIN1251</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>LATIN1</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>LATIN1</I
></SPAN
>,
         <TT
CLASS="LITERAL"
>MULE_INTERNAL</TT
>,
         <TT
CLASS="LITERAL"
>UTF8</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>LATIN2</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>LATIN2</I
></SPAN
>,
         <TT
CLASS="LITERAL"
>MULE_INTERNAL</TT
>,
         <TT
CLASS="LITERAL"
>UTF8</TT
>,
         <TT
CLASS="LITERAL"
>WIN1250</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>LATIN3</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>LATIN3</I
></SPAN
>,
         <TT
CLASS="LITERAL"
>MULE_INTERNAL</TT
>,
         <TT
CLASS="LITERAL"
>UTF8</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>LATIN4</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>LATIN4</I
></SPAN
>,
         <TT
CLASS="LITERAL"
>MULE_INTERNAL</TT
>,
         <TT
CLASS="LITERAL"
>UTF8</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>LATIN5</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>LATIN5</I
></SPAN
>,
         <TT
CLASS="LITERAL"
>UTF8</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>LATIN6</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>LATIN6</I
></SPAN
>,
         <TT
CLASS="LITERAL"
>UTF8</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>LATIN7</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>LATIN7</I
></SPAN
>,
         <TT
CLASS="LITERAL"
>UTF8</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>LATIN8</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>LATIN8</I
></SPAN
>,
         <TT
CLASS="LITERAL"
>UTF8</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>LATIN9</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>LATIN9</I
></SPAN
>,
         <TT
CLASS="LITERAL"
>UTF8</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>LATIN10</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>LATIN10</I
></SPAN
>,
         <TT
CLASS="LITERAL"
>UTF8</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>MULE_INTERNAL</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>MULE_INTERNAL</I
></SPAN
>,
          <TT
CLASS="LITERAL"
>BIG5</TT
>,
          <TT
CLASS="LITERAL"
>EUC_CN</TT
>,
          <TT
CLASS="LITERAL"
>EUC_JP</TT
>,
          <TT
CLASS="LITERAL"
>EUC_KR</TT
>,
          <TT
CLASS="LITERAL"
>EUC_TW</TT
>,
          <TT
CLASS="LITERAL"
>ISO_8859_5</TT
>,
          <TT
CLASS="LITERAL"
>KOI8</TT
>,
          <TT
CLASS="LITERAL"
>LATIN1</TT
> to <TT
CLASS="LITERAL"
>LATIN4</TT
>,
          <TT
CLASS="LITERAL"
>SJIS</TT
>,
          <TT
CLASS="LITERAL"
>WIN866</TT
>,
          <TT
CLASS="LITERAL"
>WIN1250</TT
>,
          <TT
CLASS="LITERAL"
>WIN1251</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>SJIS</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>not supported as a server encoding</I
></SPAN
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>SQL_ASCII</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>any (no conversion will be performed)</I
></SPAN
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>UHC</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>not supported as a server encoding</I
></SPAN
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>UTF8</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>all supported encodings</I
></SPAN
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>WIN866</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>WIN866</I
></SPAN
>,
          <TT
CLASS="LITERAL"
>ISO_8859_5</TT
>,
          <TT
CLASS="LITERAL"
>KOI8</TT
>,
          <TT
CLASS="LITERAL"
>MULE_INTERNAL</TT
>,
          <TT
CLASS="LITERAL"
>UTF8</TT
>,
          <TT
CLASS="LITERAL"
>WIN1251</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>WIN874</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>WIN874</I
></SPAN
>,
         <TT
CLASS="LITERAL"
>UTF8</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>WIN1250</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>WIN1250</I
></SPAN
>,
          <TT
CLASS="LITERAL"
>LATIN2</TT
>,
          <TT
CLASS="LITERAL"
>MULE_INTERNAL</TT
>,
          <TT
CLASS="LITERAL"
>UTF8</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>WIN1251</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>WIN1251</I
></SPAN
>,
          <TT
CLASS="LITERAL"
>ISO_8859_5</TT
>,
          <TT
CLASS="LITERAL"
>KOI8</TT
>,
          <TT
CLASS="LITERAL"
>MULE_INTERNAL</TT
>,
          <TT
CLASS="LITERAL"
>UTF8</TT
>,
          <TT
CLASS="LITERAL"
>WIN866</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>WIN1252</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>WIN1252</I
></SPAN
>,
          <TT
CLASS="LITERAL"
>UTF8</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>WIN1253</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>WIN1253</I
></SPAN
>,
          <TT
CLASS="LITERAL"
>UTF8</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>WIN1254</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>WIN1254</I
></SPAN
>,
          <TT
CLASS="LITERAL"
>UTF8</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>WIN1255</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>WIN1255</I
></SPAN
>,
          <TT
CLASS="LITERAL"
>UTF8</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>WIN1256</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>WIN1256</I
></SPAN
>,
         <TT
CLASS="LITERAL"
>UTF8</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>WIN1257</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>WIN1257</I
></SPAN
>,
          <TT
CLASS="LITERAL"
>UTF8</TT
>
         </TD
></TR
><TR
><TD
><TT
CLASS="LITERAL"
>WIN1258</TT
></TD
><TD
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>WIN1258</I
></SPAN
>,
         <TT
CLASS="LITERAL"
>UTF8</TT
>
         </TD
></TR
></TBODY
></TABLE
></DIV
><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
></P
></P><UL
><LI
><P
>        Using the <TT
CLASS="COMMAND"
>\encoding</TT
> command in
        <SPAN
CLASS="APPLICATION"
>psql</SPAN
>.
        <TT
CLASS="COMMAND"
>\encoding</TT
> allows you to change client
        encoding on the fly. For
        example, to change the encoding to <TT
CLASS="LITERAL"
>SJIS</TT
>, type:

</P><PRE
CLASS="PROGRAMLISTING"
>\encoding SJIS</PRE
><P>
       </P
></LI
><LI
><P
>        <SPAN
CLASS="APPLICATION"
>libpq</SPAN
> (<A
HREF="libpq-control.html"
>Section 30.9</A
>) has functions to control the client encoding.
       </P
></LI
><LI
><P
>        Using <TT
CLASS="COMMAND"
>SET client_encoding TO</TT
>.

        Setting the client encoding can be done with this SQL command:

</P><PRE
CLASS="PROGRAMLISTING"
>SET CLIENT_ENCODING TO '<TT
CLASS="REPLACEABLE"
><I
>value</I
></TT
>';</PRE
><P>

        Also you can use the standard SQL syntax <TT
CLASS="LITERAL"
>SET NAMES</TT
>
        for this purpose:

</P><PRE
CLASS="PROGRAMLISTING"
>SET NAMES '<TT
CLASS="REPLACEABLE"
><I
>value</I
></TT
>';</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
><P
>        Using <TT
CLASS="ENVAR"
>PGCLIENTENCODING</TT
>. If the environment variable
        <TT
CLASS="ENVAR"
>PGCLIENTENCODING</TT
> 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
><P
>       Using the configuration variable <A
HREF="runtime-config-client.html#GUC-CLIENT-ENCODING"
>client_encoding</A
>. If the
       <TT
CLASS="VARNAME"
>client_encoding</TT
> 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
><P>
    </P
><P
>     If the conversion of a particular character is not possible
     &mdash; suppose you chose <TT
CLASS="LITERAL"
>EUC_JP</TT
> for the
     server and <TT
CLASS="LITERAL"
>LATIN1</TT
> for the client, then some
     Japanese characters do not have a representation in
     <TT
CLASS="LITERAL"
>LATIN1</TT
> &mdash; then an error is reported.
    </P
><P
>     If the client character set is defined as <TT
CLASS="LITERAL"
>SQL_ASCII</TT
>,
     encoding conversion is disabled, regardless of the server's character
     set.  Just as for the server, use of <TT
CLASS="LITERAL"
>SQL_ASCII</TT
> is unwise
     unless you are working with all-ASCII data.
    </P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN27808"
>22.2.4. Further Reading</A
></H2
><P
>     These are good sources to start learning about various kinds of encoding
     systems.

     <P
></P
></P><DIV
CLASS="VARIABLELIST"
><DL
><DT
><A
HREF="http://www.i18ngurus.com/docs/984813247.html"
TARGET="_top"
>http://www.i18ngurus.com/docs/984813247.html</A
></DT
><DD
><P
>         An extensive collection of documents about character sets, encodings,
         and code pages.
        </P
></DD
><DT
><A
HREF="ftp://ftp.ora.com/pub/examples/nutshell/ujip/doc/cjk.inf"
TARGET="_top"
>ftp://ftp.ora.com/pub/examples/nutshell/ujip/doc/cjk.inf</A
></DT
><DD
><P
>         Detailed explanations of <TT
CLASS="LITERAL"
>EUC_JP</TT
>,
         <TT
CLASS="LITERAL"
>EUC_CN</TT
>, <TT
CLASS="LITERAL"
>EUC_KR</TT
>,
         <TT
CLASS="LITERAL"
>EUC_TW</TT
> appear in section 3.2.
        </P
></DD
><DT
><A
HREF="http://www.unicode.org/"
TARGET="_top"
>http://www.unicode.org/</A
></DT
><DD
><P
>         The web site of the Unicode Consortium
        </P
></DD
><DT
>RFC 3629</DT
><DD
><P
>         <ACRONYM
CLASS="ACRONYM"
>UTF</ACRONYM
>-8 is defined here.
        </P
></DD
></DL
></DIV
><P>
    </P
></DIV
></DIV
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