Apart from
   bug fixes, the following were the major enhancements:

   <itemizedlist>
    <listitem>
     <para>
      The query language PostQUEL was replaced with
      <acronym>SQL</acronym> (implemented in the server).  (Interface
      library <link linkend="libpq">libpq</link> was named after PostQUEL.)
      Subqueries
      were not supported until <productname>PostgreSQL</productname>
      (see below), but they could be imitated in
      <productname>Postgres95</productname> with user-defined
      <acronym>SQL</acronym> functions. Aggregate functions were
      re-implemented.  Support for the <literal>GROUP BY</literal>
      query clause was also added.
     </para>
    </listitem>

    <listitem>
     <para>
      A new program
      (<application>psql</application>) was provided for interactive
      SQL queries, which used <acronym>GNU</acronym>
      <application>Readline</application>.  This largely superseded
      the old <application>monitor</application> program.
     </para>
    </listitem>

    <listitem>
     <para>
      A new front-end library, <filename>libpgtcl</filename>,
      supported <acronym>Tcl</acronym>-based clients.  A sample shell,
      <command>pgtclsh</command>, provided new Tcl commands to
      interface <application>Tcl</application> programs with the
      <productname>Postgres95</productname> server.
     </para>
    </listitem>

    <listitem>
     <para>
      The large-object interface was overhauled. The inversion large
      objects were the only mechanism for storing large objects.  (The
      inversion file system was removed.)
     </para>
    </listitem>

    <listitem>
     <para>
      The instance-level rule system was removed.  Rules were still
      available as rewrite rules.
     </para>
    </listitem>

    <listitem>
     <para>
      A short tutorial introducing regular <acronym>SQL</acronym>
      features as well as those of
      <productname>Postgres95</productname> was distributed with the
      source code
     </para>
    </listitem>

    <listitem>
     <para>
      <acronym>GNU</acronym> make (instead of <acronym>BSD</acronym>
      make) was used for the build.  Also,
      <productname>Postgres95</productname> could be compiled with an
      unpatched <productname>GCC</productname> (data alignment of
      doubles was fixed).
     </para>
    </listitem>
   </itemizedlist>
  </para>
 </sect2>

 <sect2 id="history-postgresql">
  <title><productname>PostgreSQL</productname></title>

  <para>
   By 1996, it became clear that the name <quote>Postgres95</quote>
   would not stand the test of time. We chose a new name,
   <productname>PostgreSQL</productname>, to reflect the relationship
   between the original <productname>POSTGRES</productname> and the
   more recent versions with <acronym>SQL</acronym> capability.  At
   the same time, we set the version numbering to start at 6.0,
   putting the numbers back into the sequence originally begun by the
   Berkeley <productname>POSTGRES</productname> project.
  </para>

  <para>
   <productname>Postgres</productname> is still considered an official
   project name, both because of tradition and because people find it
   easier to pronounce <productname>Postgres</productname> than
   <productname>PostgreSQL</productname>.
  </para>

  <para>
   The emphasis during development of
   <productname>Postgres95</productname> was on identifying and
   understanding existing problems in the server code.  With
   <productname>PostgreSQL</productname>, the emphasis has shifted to
   augmenting features and capabilities, although work continues in
   all areas.
  </para>

  <para>
   Details about what has happened in
   each <productname>PostgreSQL</productname> release since then
   can be found at
   <ulink url="https://www.postgresql.org/docs/release/">https://www.postgresql.org/docs/release/</ulink>.
  </para>
 </sect2>
</sect1>