'ENCODING',
  datlocprovider => 'LOCALE_PROVIDER', datistemplate => 't',
  datallowconn => 't', dathasloginevt => 'f', datconnlimit => '-1', datfrozenxid => '0',
  datminmxid => '1', dattablespace => 'pg_default', datcollate => 'LC_COLLATE',
  datctype => 'LC_CTYPE', datlocale => 'DATLOCALE', datacl => '_null_' },

]
]]></programlisting>

   <para>
    Points to note:
   </para>

   <itemizedlist>

    <listitem>
     <para>
      The overall file layout is: open square bracket, one or more sets of
      curly braces each of which represents a catalog row, close square
      bracket.  Write a comma after each closing curly brace.
     </para>
    </listitem>

    <listitem>
     <para>
      Within each catalog row, write comma-separated
      <replaceable>key</replaceable> <literal>=&gt;</literal>
      <replaceable>value</replaceable> pairs.  The
      allowed <replaceable>key</replaceable>s are the names of the catalog's
      columns, plus the metadata keys <literal>oid</literal>,
      <literal>oid_symbol</literal>,
      <literal>array_type_oid</literal>, and <literal>descr</literal>.
      (The use of <literal>oid</literal> and <literal>oid_symbol</literal>
      is described in <xref linkend="system-catalog-oid-assignment"/> below,
      while <literal>array_type_oid</literal> is described in
      <xref linkend="system-catalog-auto-array-types"/>.
      <literal>descr</literal> supplies a description string for the object,
      which will be inserted into <structname>pg_description</structname>
      or <structname>pg_shdescription</structname> as appropriate.)
      While the metadata keys are optional, the catalog's defined columns
      must all be provided, except when the catalog's <literal>.h</literal>
      file specifies a default value for the column.
      (In the example above, the <structfield>datdba</structfield> field has
      been omitted because <filename>pg_database.h</filename> supplies a
      suitable default value for it.)
     </para>
    </listitem>

    <listitem>
     <para>
      All values must be single-quoted.  Escape single quotes used within a
      value with a backslash.  Backslashes meant as data can, but need not,
      be doubled; this follows Perl's rules for simple quoted literals.
      Note that backslashes appearing as data will be treated as escapes by
      the bootstrap scanner, according to the same rules as for escape string
      constants (see <xref linkend="sql-syntax-strings-escape"/>); for
      example <literal>\t</literal> converts to a tab character.  If you
      actually want a backslash in the final value, you will need to write
      four of them: Perl strips two, leaving <literal>\\</literal> for the
      bootstrap scanner to see.
     </para>
    </listitem>

    <listitem>
     <para>
      Null values are represented by <literal>_null_</literal>.
      (Note that there is no way to create a value that is just that
      string.)
     </para>
    </listitem>

    <listitem>
     <para>
      Comments are preceded by <literal>#</literal>, and must be on their
      own lines.
     </para>
    </listitem>

    <listitem>
     <para>
      Field values that are OIDs of other catalog entries should be
      represented by symbolic names rather than actual numeric OIDs.
      (In the example above, <structfield>dattablespace</structfield>
      contains such a reference.)
      This is described in <xref linkend="system-catalog-oid-references"/>
      below.
     </para>
    </listitem>

    <listitem>
     <para>
      Since hashes are unordered data structures, field order and line
      layout aren't semantically significant.  However, to maintain a
      consistent appearance, we set a few rules that are applied by the
      formatting script <filename>reformat_dat_file.pl</filename>:

      <itemizedlist>

       <listitem>
        <para>
         Within each pair of curly braces, the metadata
         fields <literal>oid</literal>, <literal>oid_symbol</literal>,