alter_role.sgml

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

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$PostgreSQL: pgsql/doc/src/sgml/ref/alter_role.sgml,v 1.2 2005/07/31 17:19:17 tgl Exp $
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<refentry id="SQL-ALTERROLE">
 <refmeta>
  <refentrytitle id="sql-alterrole-title">ALTER ROLE</refentrytitle>
  <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>parameter</replaceable> { TO | = } { <replaceable>value</replaceable> | DEFAULT }
ALTER ROLE <replaceable class="PARAMETER">name</replaceable> RESET <replaceable>parameter</replaceable>
</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">,
   which see for details.  (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 third and the fourth variant 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 <command>postmaster</command> command line.
   (For a role without <literal>LOGIN</> privilege, session defaults have
   no effect.)
   Ordinary roles can change their own session defaults.
   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">,
        which see for more information.
       </para>
      </listitem>
     </varlistentry>

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

     <varlistentry>
      <term><replaceable>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.
       </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>
   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>
   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>

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