alter_database.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_database.sgml,v 1.17 2005/10/13 22:44:51 tgl Exp $
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<refentry id="SQL-ALTERDATABASE">
 <refmeta>
  <refentrytitle id="sql-alterdatabase-title">ALTER DATABASE</refentrytitle>
  <refmiscinfo>SQL - Language Statements</refmiscinfo>
 </refmeta>

 <refnamediv>
  <refname>ALTER DATABASE</refname>
  <refpurpose>change a database</refpurpose>
 </refnamediv>

 <indexterm zone="sql-alterdatabase">
  <primary>ALTER DATABASE</primary>
 </indexterm>

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

where <replaceable class="PARAMETER">option</replaceable> can be:

    CONNECTION LIMIT <replaceable class="PARAMETER">connlimit</replaceable>

ALTER DATABASE <replaceable class="PARAMETER">name</replaceable> SET <replaceable>parameter</replaceable> { TO | = } { <replaceable>value</replaceable> | DEFAULT }
ALTER DATABASE <replaceable class="PARAMETER">name</replaceable> RESET <replaceable>parameter</replaceable>

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

ALTER DATABASE <replaceable class="PARAMETER">name</replaceable> OWNER TO <replaceable>new_owner</replaceable>
</synopsis>
 </refsynopsisdiv>

 <refsect1>
  <title>Description</title>

  <para>
   <command>ALTER DATABASE</command> changes the attributes
   of a database.
  </para>

  <para>
   The first form changes certain per-database settings.  (See below for
   details.)  Only the database owner or a superuser can change these settings.
  </para> 

  <para>
   The second and third forms change the session default for a run-time
   configuration variable for a <productname>PostgreSQL</productname>
   database. Whenever a new session is subsequently started in that
   database, the specified value becomes the session default value.
   The database-specific default overrides whatever setting is present
   in <filename>postgresql.conf</> or has been received from the
   <command>postmaster</command> command line.  Only the database
   owner or a superuser can change the session defaults for a
   database.  Certain variables cannot be set this way, or can only be
   set by a superuser.
  </para>

  <para>
   The fourth form changes the name of the database.  Only the database
   owner or a superuser can rename a database; non-superuser owners must
   also have the
   <literal>CREATEDB</literal> privilege.  The current database cannot
   be renamed.  (Connect to a different database if you need to do
   that.)
  </para>

  <para>
   The fifth form changes the owner of the database.
   To alter the owner, you must own the database and also be a direct or
   indirect member of the new owning role, and you must have the
   <literal>CREATEDB</literal> privilege.
   (Note that superusers have all these privileges automatically.)
  </para>
 </refsect1>

 <refsect1>
  <title>Parameters</title>

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

     <varlistentry>
      <term><replaceable class="parameter">connlimit</replaceable></term>
      <listitem>
       <para>
        How many concurrent connections can be made
        to this database.  -1 means no limit.
       </para>
      </listitem>
     </varlistentry> 

     <varlistentry>
      <term><replaceable>parameter</replaceable></term>
      <term><replaceable>value</replaceable></term>
      <listitem>
       <para>
        Set this database'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
        database-specific setting is removed, so the system-wide default
        setting will be inherited in new sessions.  Use <literal>RESET
        ALL</literal> to clear all database-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>

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

   <varlistentry>
    <term><replaceable class="parameter">new_owner</replaceable></term>
    <listitem>
     <para>
      The new owner of the database.
     </para>
    </listitem>
   </varlistentry>
  </variablelist>
 </refsect1>

 <refsect1>
  <title>Notes</title>

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

 <refsect1>
  <title>Examples</title>

  <para>
   To disable index scans by default in the database
   <literal>test</literal>:

<programlisting>
ALTER DATABASE test SET enable_indexscan TO off;
</programlisting>
  </para>
 </refsect1>

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

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

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

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