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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>CREATE CONVERSION</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="sql-createcollation.html" title="CREATE COLLATION" /><link rel="next" href="sql-createdatabase.html" title="CREATE DATABASE" /></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">CREATE CONVERSION</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="sql-createcollation.html" title="CREATE COLLATION">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="sql-commands.html" title="SQL Commands">Up</a></td><th width="60%" align="center">SQL Commands</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="sql-createdatabase.html" title="CREATE DATABASE">Next</a></td></tr></table><hr></hr></div><div class="refentry" id="SQL-CREATECONVERSION"><div class="titlepage"></div><a id="id-1.9.3.60.1" class="indexterm"></a><div class="refnamediv"><h2><span class="refentrytitle">CREATE CONVERSION</span></h2><p>CREATE CONVERSION — define a new encoding conversion</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><pre class="synopsis">
CREATE [ DEFAULT ] CONVERSION <em class="replaceable"><code>name</code></em>
FOR <em class="replaceable"><code>source_encoding</code></em> TO <em class="replaceable"><code>dest_encoding</code></em> FROM <em class="replaceable"><code>function_name</code></em>
</pre></div><div class="refsect1" id="SQL-CREATECONVERSION-DESCRIPTION"><h2>Description</h2><p>
<code class="command">CREATE CONVERSION</code> defines a new conversion between
character set encodings. Also, conversions that
are marked <code class="literal">DEFAULT</code> can be used for automatic encoding
conversion between
client and server. For this purpose, two conversions, from encoding A to
B <span class="emphasis"><em>and</em></span> from encoding B to A, must be defined.
</p><p>
To be able to create a conversion, you must have <code class="literal">EXECUTE</code> privilege
on the function and <code class="literal">CREATE</code> privilege on the destination schema.
</p></div><div class="refsect1" id="id-1.9.3.60.6"><h2>Parameters</h2><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="literal">DEFAULT</code></span></dt><dd><p>
The <code class="literal">DEFAULT</code> clause indicates that this conversion
is the default for this particular source to destination
encoding. There should be only one default encoding in a schema
for the encoding pair.
</p></dd><dt><span class="term"><em class="replaceable"><code>name</code></em></span></dt><dd><p>
The name of the conversion. The conversion name can be
schema-qualified. If it is not, the conversion is defined in the
current schema. The conversion name must be unique within a
schema.
</p></dd><dt><span class="term"><em class="replaceable"><code>source_encoding</code></em></span></dt><dd><p>
The source encoding name.
</p></dd><dt><span class="term"><em class="replaceable"><code>dest_encoding</code></em></span></dt><dd><p>
The destination encoding name.
</p></dd><dt><span class="term"><em class="replaceable"><code>function_name</code></em></span></dt><dd><p>
The function used to perform the conversion. The function name can
be schema-qualified. If it is not, the function will be looked
up in the path.
</p><p>
The function must have the following signature:
</p><pre class="programlisting">
conv_proc(
integer, -- source encoding ID
integer, -- destination encoding ID
cstring, -- source string (null terminated C string)
internal, -- destination (fill with a null terminated C string)
integer -- source string length
) RETURNS void;
</pre></dd></dl></div></div><div class="refsect1" id="SQL-CREATECONVERSION-NOTES"><h2>Notes</h2><p>
Use <code class="command">DROP CONVERSION</code> to remove user-defined conversions.
</p><p>
The privileges required to create a conversion might be changed in a future
release.
</p></div><div class="refsect1" id="SQL-CREATECONVERSION-EXAMPLES"><h2>Examples</h2><p>
To create a conversion from encoding <code class="literal">UTF8</code> to
<code class="literal">LATIN1</code> using <code class="function">myfunc</code>:
</p><pre class="programlisting">
CREATE CONVERSION myconv FOR 'UTF8' TO 'LATIN1' FROM myfunc;
</pre></div><div class="refsect1" id="SQL-CREATECONVERSION-COMPAT"><h2>Compatibility</h2><p>
<code class="command">CREATE CONVERSION</code>
is a <span class="productname">PostgreSQL</span> extension.
There is no <code class="command">CREATE CONVERSION</code>
statement in the SQL standard, but a <code class="command">CREATE TRANSLATION</code>
statement that is very similar in purpose and syntax.
</p></div><div class="refsect1" id="SQL-CREATECONVERSION-SEEALSO"><h2>See Also</h2><span class="simplelist"><a class="xref" href="sql-alterconversion.html" title="ALTER CONVERSION"><span class="refentrytitle">ALTER CONVERSION</span></a>, <a class="xref" href="sql-createfunction.html" title="CREATE FUNCTION"><span class="refentrytitle">CREATE FUNCTION</span></a>, <a class="xref" href="sql-dropconversion.html" title="DROP CONVERSION"><span class="refentrytitle">DROP CONVERSION</span></a></span></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="sql-createcollation.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="sql-commands.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="sql-createdatabase.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">CREATE COLLATION </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> CREATE DATABASE</td></tr></table></div></body></html>
