Top.Science.Astronomy.Astrophysics
 Top.Science.Astronomy.Cosmology
(4 rows)
</screen>
  </para>

  <para>
   Here are some examples of path matching:
<screen>
ltreetest=&gt; SELECT path FROM test WHERE path ~ '*.Astronomy.*';
                     path
-----------------------------------------------
 Top.Science.Astronomy
 Top.Science.Astronomy.Astrophysics
 Top.Science.Astronomy.Cosmology
 Top.Collections.Pictures.Astronomy
 Top.Collections.Pictures.Astronomy.Stars
 Top.Collections.Pictures.Astronomy.Galaxies
 Top.Collections.Pictures.Astronomy.Astronauts
(7 rows)

ltreetest=&gt; SELECT path FROM test WHERE path ~ '*.!pictures@.Astronomy.*';
                path
------------------------------------
 Top.Science.Astronomy
 Top.Science.Astronomy.Astrophysics
 Top.Science.Astronomy.Cosmology
(3 rows)
</screen>
  </para>

  <para>
   Here are some examples of full text search:
<screen>
ltreetest=&gt; SELECT path FROM test WHERE path @ 'Astro*% &amp; !pictures@';
                path
------------------------------------
 Top.Science.Astronomy
 Top.Science.Astronomy.Astrophysics
 Top.Science.Astronomy.Cosmology
 Top.Hobbies.Amateurs_Astronomy
(4 rows)

ltreetest=&gt; SELECT path FROM test WHERE path @ 'Astro* &amp; !pictures@';
                path
------------------------------------
 Top.Science.Astronomy
 Top.Science.Astronomy.Astrophysics
 Top.Science.Astronomy.Cosmology
(3 rows)
</screen>
  </para>

  <para>
   Path construction using functions:
<screen>
ltreetest=&gt; SELECT subpath(path,0,2)||'Space'||subpath(path,2) FROM test WHERE path &lt;@ 'Top.Science.Astronomy';
                 ?column?
------------------------------------------
 Top.Science.Space.Astronomy
 Top.Science.Space.Astronomy.Astrophysics
 Top.Science.Space.Astronomy.Cosmology
(3 rows)
</screen>
  </para>

  <para>
   We could simplify this by creating an SQL function that inserts a label
   at a specified position in a path:
<screen>
CREATE FUNCTION ins_label(ltree, int, text) RETURNS ltree
    AS 'select subpath($1,0,$2) || $3 || subpath($1,$2);'
    LANGUAGE SQL IMMUTABLE;

ltreetest=&gt; SELECT ins_label(path,2,'Space') FROM test WHERE path &lt;@ 'Top.Science.Astronomy';
                ins_label
------------------------------------------
 Top.Science.Space.Astronomy
 Top.Science.Space.Astronomy.Astrophysics
 Top.Science.Space.Astronomy.Cosmology
(3 rows)
</screen>
  </para>
 </sect2>

 <sect2 id="ltree-transforms">
  <title>Transforms</title>

  <para>
   The <literal>ltree_plpython3u</literal> extension implements transforms for
   the <type>ltree</type> type for PL/Python. If installed and specified when
   creating a function, <type>ltree</type> values are mapped to Python lists.
   (The reverse is currently not supported, however.)
  </para>
 </sect2>

 <sect2 id="ltree-authors">
  <title>Authors</title>

  <para>
   All work was done by Teodor Sigaev (<email>teodor@stack.net</email>) and
   Oleg Bartunov (<email>oleg@sai.msu.su</email>). See
   <ulink url="http://www.sai.msu.su/~megera/postgres/gist/"></ulink> for
   additional information. Authors would like to thank Eugeny Rodichev for
   helpful discussions. Comments and bug reports are welcome.
  </para>
 </sect2>

</sect1>