postgresql/doc/src/sgml/ref/create_database.sgml

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$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_database.sgml,v 1.34 2003/04/22 10:08:08 petere Exp $
PostgreSQL documentation
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<refentry id="SQL-CREATEDATABASE">
 <refmeta>
  <refentrytitle id="sql-createdatabase-title">CREATE DATABASE</refentrytitle>
  <refmiscinfo>SQL - Language Statements</refmiscinfo>
 </refmeta>

 <refnamediv>
  <refname>CREATE DATABASE</refname>
  <refpurpose>create a new database</refpurpose>
 </refnamediv>

 <refsynopsisdiv>
<synopsis>
CREATE DATABASE <replaceable class="PARAMETER">name</replaceable>
    [ [ WITH ] [ OWNER [=] <replaceable class="parameter">dbowner</replaceable> ]
           [ LOCATION [=] '<replaceable class="parameter">dbpath</replaceable>' ]
           [ TEMPLATE [=] <replaceable class="parameter">template</replaceable> ]
           [ ENCODING [=] <replaceable class="parameter">encoding</replaceable> ] ]
</synopsis>
 </refsynopsisdiv>

 <refsect1>
  <title>Description</title>

  <para>
   <command>CREATE DATABASE</command> creates a new
   <productname>PostgreSQL</productname> database.
  </para>

  <para>
   Normally, the creator becomes the owner of the new database.
   Superusers can create databases owned by other users using the
   <literal>OWNER</> clause. They can even create databases owned by
   users with no special privileges. Non-superusers with <literal>CREATEDB</>
   privilege can only create databases owned by themselves.
  </para>

  <para>
   An alternative location can be specified in order to,
   for example, store the database on a different disk.
   The path must have been prepared with the 
   <xref linkend="APP-INITLOCATION" endterm="APP-INITLOCATION-title">
   command.
  </para>

  <para>
   If the path name does not contain a slash, it is interpreted
   as an environment variable name, which must be known to the
   server process. This way the database administrator can
   exercise control over locations in which databases can be created.
   (A customary choice is, e.g., <envar>PGDATA2</envar>.)
   If the server is compiled with <literal>ALLOW_ABSOLUTE_DBPATHS</literal>
   (not so by default), absolute path names, as identified by
   a leading slash
   (e.g., <filename>/usr/local/pgsql/data</filename>),
   are allowed as well.
  </para>

  <para>
   By default, the new database will be created by cloning the standard
   system database <literal>template1</>.  A different template can be
   specified by writing <literal>TEMPLATE
   <replaceable class="parameter">name</replaceable></literal>.  In particular,
   by writing <literal>TEMPLATE template0</>, you can create a virgin
   database containing only the standard objects predefined by your
   version of <productname>PostgreSQL</productname>.  This is useful
   if you wish to avoid copying
   any installation-local objects that may have been added to
   <literal>template1</>. 
  </para>

  <para>
   The optional encoding parameter allows selection of the database
   encoding.  When not specified, it defaults to the encoding used by
   the selected template database.
  </para>
 </refsect1>

 <refsect1>
  <title>Parameter</title>

    <variablelist>
     <varlistentry>
      <term><replaceable class="parameter">name</replaceable></term>
      <listitem>
       <para>
	The name of a database to create.
       </para>
      </listitem>
     </varlistentry>
     <varlistentry>
      <term><replaceable class="parameter">dbowner</replaceable></term>
      <listitem>
       <para>
        The name of the database user who will own the new database,
	or <literal>DEFAULT</literal> to use the default (namely, the
	user executing the command).
       </para>
      </listitem>
     </varlistentry>
     <varlistentry>
      <term><replaceable class="parameter">dbpath</replaceable></term>
      <listitem>
       <para>
	An alternate file-system location in which to store the new database,
	specified as a string literal;
	or <literal>DEFAULT</literal> to use the default location.
       </para>
      </listitem>
     </varlistentry>
     <varlistentry>
      <term><replaceable class="parameter">template</replaceable></term>
      <listitem>
       <para>
        The name of the template from which to create the new database,
	or <literal>DEFAULT</literal> to use the default template
	(<literal>template1</literal>).
       </para>
      </listitem>
     </varlistentry>
     <varlistentry>
      <term><replaceable class="parameter">encoding</replaceable></term>
      <listitem>
       <para>
        Character set encoding to use in the new database.  Specify
	a string constant (e.g., <literal>'SQL_ASCII'</literal>),
	or an integer encoding number, or <literal>DEFAULT</literal>
	to use the default encoding.
       </para>
      </listitem>
     </varlistentry>
    </variablelist>

  <para>
   Optional parameters can be written in any order, not only the order
   illustrated above.
  </para>
 </refsect1>

 <refsect1>
  <title>Diagnostics</title>

    <variablelist>
     <varlistentry>
      <term><computeroutput>CREATE DATABASE</computeroutput></term>
      <listitem>
       <para>
	Message returned if the database was successfully created.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><computeroutput>ERROR:  user '<replaceable class="parameter">username</replaceable>' is not allowed to create/drop databases</computeroutput></term>
      <listitem>
       <para>
        You must have the special <literal>CREATEDB</> privilege to create databases.
        See <xref linkend="SQL-CREATEUSER" endterm="SQL-CREATEUSER-title">.
       </para>
      </listitem>
     </varlistentry>


     <varlistentry>
      <term><computeroutput>ERROR:  createdb: database "<replaceable class="parameter">name</replaceable>" already exists</computeroutput></term>
      <listitem>
       <para>
	This occurs if a database with the specified name already
	exists.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><computeroutput>ERROR:  database path may not contain single quotes</computeroutput></term>
      <listitem>
       <para>
	The database location
        <replaceable class="parameter">dbpath</replaceable> cannot contain
        single quotes. This is required so that the shell commands that
        create the database directory can execute safely.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><computeroutput>ERROR:  CREATE DATABASE: may not be called in a transaction block</computeroutput></term>
      <listitem>
       <para>
        If you have an explicit transaction block in progress you cannot call
        <command>CREATE DATABASE</command>. You must finish the transaction first.
       </para>
      </listitem>
     </varlistentry>

     <varlistentry>
      <term><computeroutput>ERROR:  Unable to create database directory '<replaceable>path</replaceable>'.</computeroutput></term>
      <term><computeroutput>ERROR:  Could not initialize database directory.</computeroutput></term>
      <listitem>
       <para>
        These are most likely related to insufficient permissions on the data
        directory, a full disk, or other file system problems. The user under
        which the database server is running must have access to the location.
       </para>
      </listitem>
     </varlistentry>

    </variablelist>
 </refsect1>

 <refsect1>
  <title>Notes</title>

   <para>
    Use <xref linkend="SQL-DROPDATABASE" endterm="SQL-DROPDATABASE-title"> to remove a database.
   </para>

   <para>
    The program <xref linkend="APP-CREATEDB" endterm="APP-CREATEDB-title"> is a
    wrapper program around this command, provided for convenience.
   </para>

  <para>
   There are security issues involved with using alternate database
   locations specified with absolute path names.  See <xref
   linkend="manage-ag-alternate-locs"> for more information.
  </para>

  <para>
   Although it is possible to copy a database other than <literal>template1</>
   by specifying its name as the template, this is not (yet) intended as
   a general-purpose <quote><command>COPY DATABASE</command></quote> facility.
   We recommend that databases used as templates be treated as read-only.
   See <xref linkend="manage-ag-templatedbs"> for more information.
  </para>
 </refsect1>

 <refsect1>
  <title>Examples</title>

  <para>
   To create a new database:

<programlisting>
CREATE DATABASE lusiadas;
</programlisting>
  </para>

  <para>
   To create a new database in an alternate area
   <filename>~/private_db</filename>, execute the following from the
   shell:

<programlisting>
mkdir private_db
initlocation ~/private_db
</programlisting>

   Then execute the following from within a
   <application>psql</application> session:

<programlisting>
CREATE DATABASE elsewhere WITH LOCATION '/home/olly/private_db';
</programlisting>
  </para>
 </refsect1>

 <refsect1>
  <title>Compatibility</title>

  <para>
   There is no <command>CREATE DATABASE</command> statement in the SQL
   standard.  Databases are equivalent to catalogs, whose creation is
   implementation-defined.
  </para>
 </refsect1>
</refentry>

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