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doc/src/sgml/ref/alter_collation.sgml
PostgreSQL documentation
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<refentry id="sql-altercollation">
 <indexterm zone="sql-altercollation">
  <primary>ALTER COLLATION</primary>
 </indexterm>

 <refmeta>
  <refentrytitle>ALTER COLLATION</refentrytitle>
  <manvolnum>7</manvolnum>
  <refmiscinfo>SQL - Language Statements</refmiscinfo>
 </refmeta>

 <refnamediv>
  <refname>ALTER COLLATION</refname>
  <refpurpose>change the definition of a collation</refpurpose>
 </refnamediv>

 <refsynopsisdiv>
<synopsis>
ALTER COLLATION <replaceable>name</replaceable> REFRESH VERSION

ALTER COLLATION <replaceable>name</replaceable> RENAME TO <replaceable>new_name</replaceable>
ALTER COLLATION <replaceable>name</replaceable> OWNER TO { <replaceable>new_owner</replaceable> | CURRENT_ROLE | CURRENT_USER | SESSION_USER }
ALTER COLLATION <replaceable>name</replaceable> SET SCHEMA <replaceable>new_schema</replaceable>
</synopsis>
 </refsynopsisdiv>

 <refsect1>
  <title>Description</title>

  <para>
   <command>ALTER COLLATION</command> changes the definition of a
   collation.
  </para>

  <para>
   You must own the collation to use <command>ALTER COLLATION</command>.
   To alter the owner, you must be able to <literal>SET ROLE</literal> to the
   new owning role, and that role must have <literal>CREATE</literal>
   privilege on the collation's schema.
   (These restrictions enforce that altering the
   owner doesn't do anything you couldn't do by dropping and recreating the
   collation. However, a superuser can alter ownership of any collation
   anyway.)
  </para>
 </refsect1>

 <refsect1>
  <title>Parameters</title>

  <variablelist>
   <varlistentry>
    <term><replaceable class="parameter">name</replaceable></term>
    <listitem>
     <para>
      The name (optionally schema-qualified) of an existing collation.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><replaceable class="parameter">new_name</replaceable></term>
    <listitem>
     <para>
      The new name of the collation.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><replaceable class="parameter">new_owner</replaceable></term>
    <listitem>
     <para>
      The new owner of the collation.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><replaceable class="parameter">new_schema</replaceable></term>
    <listitem>
     <para>
      The new schema for the collation.
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><literal>REFRESH VERSION</literal></term>
    <listitem>
     <para>
      Update the collation's version.
      See <xref linkend="sql-altercollation-notes"/> below.
     </para>
    </listitem>
   </varlistentry>
  </variablelist>
 </refsect1>

 <refsect1 id="sql-altercollation-notes" xreflabel="Notes">
  <title>Notes</title>

  <para>
   When a collation object is created, the provider-specific version of the
   collation is recorded in the system catalog.  When the collation is used,
   the current version is
   checked against the recorded version, and a warning is issued when there is
   a mismatch, for example:
<screen>
WARNING:  collation "xx-x-icu" has version mismatch
DETAIL:  The collation in the database was created using version 1.2.3.4, but the operating system provides version 2.3.4.5.
HINT:  Rebuild all objects affected by this collation and run ALTER COLLATION pg_catalog."xx-x-icu" REFRESH VERSION,