<!--
$PostgreSQL: pgsql/doc/src/sgml/ref/alter_role.sgml,v 1.12 2009/03/28 03:26:02 momjian Exp $
PostgreSQL documentation
-->

<refentry id="SQL-ALTERROLE">
 <refmeta>
  <refentrytitle id="sql-alterrole-title">ALTER ROLE</refentrytitle>
  <manvolnum>7</manvolnum>
  <refmiscinfo>SQL - Language Statements</refmiscinfo>
 </refmeta>

 <refnamediv>
  <refname>ALTER ROLE</refname>
  <refpurpose>change a database role</refpurpose>
 </refnamediv>

 <indexterm zone="sql-alterrole">
  <primary>ALTER ROLE</primary>
 </indexterm>

 <refsynopsisdiv>
<synopsis>
ALTER ROLE <replaceable class="PARAMETER">name</replaceable> [ [ WITH ] <replaceable class="PARAMETER">option</replaceable> [ ... ] ]

where <replaceable class="PARAMETER">option</replaceable> can be:
    
      SUPERUSER | NOSUPERUSER
    | CREATEDB | NOCREATEDB
    | CREATEROLE | NOCREATEROLE
    | CREATEUSER | NOCREATEUSER
    | INHERIT | NOINHERIT
    | LOGIN | NOLOGIN
    | CONNECTION LIMIT <replaceable class="PARAMETER">connlimit</replaceable>
    | [ ENCRYPTED | UNENCRYPTED ] PASSWORD '<replaceable class="PARAMETER">password</replaceable>'
    | VALID UNTIL '<replaceable class="PARAMETER">timestamp</replaceable>' 

ALTER ROLE <replaceable class="PARAMETER">name</replaceable> RENAME TO <replaceable>newname</replaceable>

ALTER ROLE <replaceable class="PARAMETER">name</replaceable> SET <replaceable>configuration_parameter</replaceable> { TO | = } { <replaceable>value</replaceable> | DEFAULT }
ALTER ROLE <replaceable class="PARAMETER">name</replaceable> SET <replaceable>configuration_parameter</replaceable> FROM CURRENT
ALTER ROLE <replaceable class="PARAMETER">name</replaceable> RESET <replaceable>configuration_parameter</replaceable>
ALTER ROLE <replaceable class="PARAMETER">name</replaceable> RESET ALL
</synopsis>
 </refsynopsisdiv>

 <refsect1>
  <title>Description</title>

  <para>
   <command>ALTER ROLE</command> changes the attributes of a
   <productname>PostgreSQL</productname> role.
  </para>

  <para>
   The first variant of this command listed in the synopsis can change
   many of the role attributes that can be specified in 
   <xref linkend="sql-createrole" endterm="sql-createrole-title">.
   (All the possible attributes are covered,
   except that there are no options for adding or removing memberships; use
   <xref linkend="SQL-GRANT" endterm="SQL-GRANT-title"> and
   <xref linkend="SQL-REVOKE" endterm="SQL-REVOKE-title"> for that.)
   Attributes not mentioned in the command retain their previous settings.
   Database superusers can change any of these settings for any role.
   Roles having <literal>CREATEROLE</> privilege can change any of these
   settings, but only for non-superuser roles.
   Ordinary roles can only change their own password.
  </para>

  <para>
   The second variant changes the name of the role.
   Database superusers can rename any role.
   Roles having <literal>CREATEROLE</> privilege can rename non-superuser
   roles.
   The current session user cannot be renamed.
   (Connect as a different user if you need to do that.)
   Because <literal>MD5</>-encrypted passwords use the role name as
   cryptographic salt, renaming a role clears its password if the
   password is <literal>MD5</>-encrypted.
  </para>

  <para> 
   The remaining variants change a role's session default for a
   specified configuration variable. Whenever the role subsequently
   starts a new session, the specified value becomes the session
   default, overriding whatever setting is present in
   <filename>postgresql.conf</> or has been received from the postgres
   command line. This only happens at login time, so configuration
   settings associated with a role to which you've <xref
   linkend="sql-set-role" endterm="sql-set-role-title"> will be ignored.
   Superusers can change anyone's session defaults. Roles having
   <literal>CREATEROLE</> privilege can change defaults for non-superuser
   roles. Certain variables cannot be set this way, or can only be
   set if a superuser issues the command.
  </para>
 </refsect1>

 <refsect1>
  <title>Parameters</title>

    <variablelist>
     <varlistentry>
      <term><replaceable class="PARAMETER">name</replaceable></term>
      <listitem>
       <para>
        The name of the role whose attributes are to be altered.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><literal>SUPERUSER</literal></term>
      <term><literal>NOSUPERUSER</literal></term>
      <term><literal>CREATEDB</></term>
      <term><literal>NOCREATEDB</></term>
      <term><literal>CREATEROLE</literal></term>
      <term><literal>NOCREATEROLE</literal></term>
      <term><literal>CREATEUSER</literal></term>
      <term><literal>NOCREATEUSER</literal></term>
      <term><literal>INHERIT</literal></term>
      <term><literal>NOINHERIT</literal></term>
      <term><literal>LOGIN</literal></term>
      <term><literal>NOLOGIN</literal></term>
      <term><literal>CONNECTION LIMIT</literal> <replaceable class="parameter">connlimit</replaceable></term>
      <term><literal>PASSWORD</> <replaceable class="parameter">password</replaceable></term>
      <term><literal>ENCRYPTED</></term>
      <term><literal>UNENCRYPTED</></term>
      <term><literal>VALID UNTIL</literal> '<replaceable class="parameter">timestamp</replaceable>'</term>
      <listitem>
       <para>
        These clauses alter attributes originally set by
        <xref linkend="SQL-CREATEROLE"
        endterm="SQL-CREATEROLE-title">. For more information, see the
        <command>CREATE ROLE</command> reference page.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><replaceable>newname</replaceable></term>
      <listitem>
       <para>
        The new name of the role.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><replaceable>configuration_parameter</replaceable></term>
      <term><replaceable>value</replaceable></term>
      <listitem>
       <para>
        Set this role's session default for the specified configuration
        parameter to the given value.  If
        <replaceable>value</replaceable> is <literal>DEFAULT</literal>
        or, equivalently, <literal>RESET</literal> is used, the
        role-specific variable setting is removed, so the role will
        inherit the system-wide default setting in new sessions.  Use
        <literal>RESET ALL</literal> to clear all role-specific settings.
        <literal>SET FROM CURRENT</> saves the session's current value of
        the parameter as the role-specific value.
       </para>

       <para>
        Role-specific variable setting take effect only at login;
        <xref linkend="sql-set-role" endterm="sql-set-role-title">
        does not process role-specific variable settings.
       </para>

       <para>
        See <xref linkend="sql-set" endterm="sql-set-title"> and <xref
        linkend="runtime-config"> for more information about allowed
        parameter names and values.
       </para>
      </listitem>
     </varlistentry>
    </variablelist>
 </refsect1>

 <refsect1>
  <title>Notes</title>

  <para>
   Use <xref linkend="SQL-CREATEROLE" endterm="SQL-CREATEROLE-title">
   to add new roles, and <xref linkend="SQL-DROPROLE"
   endterm="SQL-DROPROLE-title"> to remove a role.
  </para>

  <para>
   <command>ALTER ROLE</command> cannot change a role's memberships.
   Use <xref linkend="SQL-GRANT" endterm="SQL-GRANT-title"> and
   <xref linkend="SQL-REVOKE" endterm="SQL-REVOKE-title">
   to do that.
  </para>

  <para>
   Caution must be exercised when specifying an unencrypted password
   with this command.  The password will be transmitted to the server
   in cleartext, and it might also be logged in the client's command
   history or the server log.  <xref linkend="app-psql"
   endterm="app-psql-title"> contains a command
   <command>\password</command> that can be used to safely change a
   role's password.
  </para>

  <para>
   It is also possible to tie a
   session default to a specific database rather than to a role; see
   <xref linkend="sql-alterdatabase" endterm="sql-alterdatabase-title">.
   Role-specific settings override database-specific
   ones if there is a conflict.
  </para>
 </refsect1>

 <refsect1>
  <title>Examples</title>

  <para>
   Change a role's password:

<programlisting>
ALTER ROLE davide WITH PASSWORD 'hu8jmn3';
</programlisting>
  </para>

  <para>
   Remove a role's password:

<programlisting>
ALTER ROLE davide WITH PASSWORD NULL;
</programlisting>
  </para>

  <para>
   Change a password expiration date, specifying that the password
   should expire at midday on 4th May 2015 using
   the time zone which is one hour ahead of <acronym>UTC</>:
<programlisting>
ALTER ROLE chris VALID UNTIL 'May 4 12:00:00 2015 +1';
</programlisting>
  </para>

  <para>
   Make a password valid forever:
<programlisting>
ALTER ROLE fred VALID UNTIL 'infinity';
</programlisting>
  </para>

  <para>
   Give a role the ability to create other roles and new databases:

<programlisting>
ALTER ROLE miriam CREATEROLE CREATEDB;
</programlisting>
  </para>

  <para>
   Give a role a non-default setting of the
   <xref linkend="guc-maintenance-work-mem"> parameter:

<programlisting>
ALTER ROLE worker_bee SET maintenance_work_mem = 100000;
</programlisting>
  </para>
 </refsect1>

 <refsect1>
  <title>Compatibility</title>
    
  <para>
   The <command>ALTER ROLE</command> statement is a
   <productname>PostgreSQL</productname> extension.
  </para>
 </refsect1>

 <refsect1>
  <title>See Also</title>

  <simplelist type="inline">
   <member><xref linkend="sql-createrole" endterm="sql-createrole-title"></member>
   <member><xref linkend="sql-droprole" endterm="sql-droprole-title"></member>
   <member><xref linkend="sql-set" endterm="sql-set-title"></member>
  </simplelist>
 </refsect1>
</refentry>
