doc/src/sgml/ref/dropdb.sgml - master - githubmirror/postgres

doc/src/sgml/ref/dropdb.sgml
317 строк9 KB
Tom Lane
Fix connection string handling in src/bin/scripts/ programs.
20 окт 2020, 02:03
20 окт 2020, 02:038e5793a
<!--
doc/src/sgml/ref/dropdb.sgml
PostgreSQL documentation
-->

<refentry id="app-dropdb">
 <indexterm zone="app-dropdb">
  <primary>dropdb</primary>
 </indexterm>

 <refmeta>
  <refentrytitle><application>dropdb</application></refentrytitle>
  <manvolnum>1</manvolnum>
  <refmiscinfo>Application</refmiscinfo>
 </refmeta>

 <refnamediv>
  <refname>dropdb</refname>
  <refpurpose>remove a <productname>PostgreSQL</productname> database</refpurpose>
 </refnamediv>

 <refsynopsisdiv>
  <cmdsynopsis>
   <command>dropdb</command>
   <arg rep="repeat"><replaceable>connection-option</replaceable></arg>
   <arg rep="repeat"><replaceable>option</replaceable></arg>
   <arg choice="plain"><replaceable>dbname</replaceable></arg>
  </cmdsynopsis>
 </refsynopsisdiv>


 <refsect1>
  <title>Description</title>

  <para>
   <application>dropdb</application> destroys an existing
   <productname>PostgreSQL</productname> database.
   The user who executes this command must be a database
   superuser or the owner of the database.
  </para>

  <para>
   <application>dropdb</application> is a wrapper around the
   <acronym>SQL</acronym> command <link linkend="sql-dropdatabase"><command>DROP DATABASE</command></link>.
   There is no effective difference between dropping databases via
   this utility and via other methods for accessing the server.
  </para>

 </refsect1>


 <refsect1>
  <title>Options</title>

  <para>
   <application>dropdb</application> accepts the following command-line arguments:

    <variablelist>
     <varlistentry>
      <term><replaceable class="parameter">dbname</replaceable></term>
      <listitem>
       <para>
        Specifies the name of the database to be removed.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-e</option></term>
      <term><option>--echo</option></term>
      <listitem>
       <para>
        Echo the commands that <application>dropdb</application> generates
        and sends to the server.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-f</option></term>
      <term><option>--force</option></term>
      <listitem>
       <para>
        Attempt to terminate all existing connections to the target database
        before dropping it.   See <xref linkend="sql-dropdatabase"/> for more
        information on this option.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-i</option></term>
      <term><option>--interactive</option></term>
      <listitem>
       <para>
       Issues a verification prompt before doing anything destructive.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
       <term><option>-V</option></term>
       <term><option>--version</option></term>
       <listitem>
       <para>
       Print the <application>dropdb</application> version and exit.
       </para>
       </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>--if-exists</option></term>
      <listitem>
       <para>
       Do not throw an error if the database does not exist. A notice is issued
       in this case.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
       <term><option>-?</option></term>
       <term><option>--help</option></term>
       <listitem>
       <para>
       Show help about <application>dropdb</application> command line
       arguments, and exit.
       </para>
       </listitem>
     </varlistentry>

    </variablelist>

  </para>

  <para>
   <application>dropdb</application> also accepts the following
   command-line arguments for connection parameters:

   <variablelist>
     <varlistentry>
      <term><option>-h <replaceable class="parameter">host</replaceable></option></term>
      <term><option>--host=<replaceable class="parameter">host</replaceable></option></term>
      <listitem>
       <para>
        Specifies the host name of the machine on which the
        server
        is running.  If the value begins with a slash, it is used
        as the directory for the Unix domain socket.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-p <replaceable class="parameter">port</replaceable></option></term>
      <term><option>--port=<replaceable class="parameter">port</replaceable></option></term>
      <listitem>
       <para>
        Specifies the TCP port or local Unix domain socket file
        extension on which the server
        is listening for connections.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-U <replaceable class="parameter">username</replaceable></option></term>
      <term><option>--username=<replaceable class="parameter">username</replaceable></option></term>
      <listitem>
       <para>
        User name to connect as.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-w</option></term>
      <term><option>--no-password</option></term>
      <listitem>
       <para>
        Never issue a password prompt.  If the server requires
        password authentication and a password is not available by
        other means such as a <filename>.pgpass</filename> file, the
        connection attempt will fail.  This option can be useful in
        batch jobs and scripts where no user is present to enter a
        password.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>-W</option></term>
      <term><option>--password</option></term>
      <listitem>
       <para>
        Force <application>dropdb</application> to prompt for a
        password before connecting to a database.
       </para>

       <para>
        This option is never essential, since
        <application>dropdb</application> will automatically prompt
        for a password if the server demands password authentication.
        However, <application>dropdb</application> will waste a
        connection attempt finding out that the server wants a password.
        In some cases it is worth typing <option>-W</option> to avoid the extra
        connection attempt.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><option>--maintenance-db=<replaceable class="parameter">dbname</replaceable></option></term>
      <listitem>
       <para>
         Specifies the name of the database to connect to in order to drop the
         target database. If not specified, the <literal>postgres</literal>
         database will be used; if that does not exist (or is the database
         being dropped), <literal>template1</literal> will be used.
         This can be a <link linkend="libpq-connstring">connection
         string</link>.  If so, connection string parameters will override any
         conflicting command line options.
       </para>
      </listitem>
     </varlistentry>
   </variablelist>
  </para>
 </refsect1>


 <refsect1>
  <title>Environment</title>

  <variablelist>
   <varlistentry>
    <term><envar>PGHOST</envar></term>
    <term><envar>PGPORT</envar></term>
    <term><envar>PGUSER</envar></term>

    <listitem>
     <para>
      Default connection parameters
     </para>
    </listitem>
   </varlistentry>

   <varlistentry>
    <term><envar>PG_COLOR</envar></term>
    <listitem>
     <para>
      Specifies whether to use color in diagnostic messages. Possible values
      are <literal>always</literal>, <literal>auto</literal> and
      <literal>never</literal>.
     </para>
    </listitem>
   </varlistentry>
  </variablelist>

  <para>
   This utility, like most other <productname>PostgreSQL</productname> utilities,
   also uses the environment variables supported by <application>libpq</application>
   (see <xref linkend="libpq-envars"/>).
  </para>

 </refsect1>


 <refsect1>
  <title>Diagnostics</title>

  <para>
   In case of difficulty, see <xref linkend="sql-dropdatabase"/>
   and <xref linkend="app-psql"/> for
   discussions of potential problems and error messages.
   The database server must be running at the
   targeted host.  Also, any default connection settings and environment
   variables used by the <application>libpq</application> front-end
   library will apply.
  </para>

 </refsect1>


 <refsect1>
  <title>Examples</title>

   <para>
    To destroy the database <literal>demo</literal> on the default
    database server:
<screen>
<prompt>$ </prompt><userinput>dropdb demo</userinput>
</screen>
   </para>

   <para>
    To destroy the database <literal>demo</literal> using the
    server on host <literal>eden</literal>, port 5000, with verification and a peek
    at the underlying command:
<screen>
<prompt>$ </prompt><userinput>dropdb -p 5000 -h eden -i -e demo</userinput>
<computeroutput>Database "demo" will be permanently deleted.
Are you sure? (y/n) </computeroutput><userinput>y</userinput>
<computeroutput>DROP DATABASE demo;</computeroutput>
</screen></para>
 </refsect1>


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

  <simplelist type="inline">
   <member><xref linkend="app-createdb"/></member>
   <member><xref linkend="sql-dropdatabase"/></member>
  </simplelist>
 </refsect1>

</refentry>