Update documentation on XML functions

doc/src/sgml/datatype.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/datatype.sgml,v 1.186 2007/01/25 11:53:50 petere Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/datatype.sgml,v 1.187 2007/01/29 13:24:30 petere Exp $ -->
 
  <chapter id="datatype">
   <title id="datatype-title">Data Types</title>
@@ -3538,86 +3538,6 @@ SET xmloption TO { DOCUMENT | CONTENT };
     processed in UTF-8, computations will be most efficient if the
     server encoding is also UTF-8.
    </para>
-
-   <para>
-    <acronym>XML</> (Extensible Markup Language) support is not
-    just the existance of an <type>xml</type> data type, but a
-    variety of features supported by a database system. These
-    capabilities include import/export, indexing, searching,
-    transforming, and <acronym>XML</> to <acronym>SQL</> mapping.
-    <productname>PostgreSQL</> supports some but not all of these
-    <acronym>XML</> capabilities.  For an overview of <acronym>XML</>
-    use in databases, see <ulink
-    url="http://www.rpbourret.com/xml/XMLAndDatabases.htm"></>.
-   </para>
-
-   <variablelist>
-   <varlistentry>
-    <term>Import/Export</term>
-    <listitem>
-
-     <para>
-      There is no facility for mapping <acronym>XML</> to relational
-      tables. An external tool must be used for this. One simple way to
-      export <acronym>XML</> is to use <application>psql</> in
-      <acronym>HTML</> mode (<literal>\pset format html</>), and convert
-      the <acronym>XHTML</> output to XML using an external tool.
-     </para>
-    </listitem>
-   </varlistentry>
-
-   <varlistentry>
-    <term>Indexing</term>
-    <listitem>
-
-     <para>
-      <filename>/contrib/xml2</> functions can be used in expression
-      indexes to index specific <acronym>XML</> fields. To index the
-      full contents of <acronym>XML</> documents, the full-text indexing
-      tool <filename>/contrib/tsearch2</> can be used. Of course,
-      Tsearch2 indexes have no <acronym>XML</> awareness so additional
-      <filename>/contrib/xml2</> checks should be added to queries.
-     </para>
-    </listitem>
-   </varlistentry>
-
-   <varlistentry>
-    <term>Searching</term>
-    <listitem>
-
-     <para>
-      XPath searches are implemented using <filename>/contrib/xml2</>.
-      It processes <acronym>XML</> text documents and returns results
-      based on the requested query.
-     </para>
-    </listitem>
-   </varlistentry>
-
-   <varlistentry>
-    <term>Transforming</term>
-    <listitem>
-
-     <para>
-      <filename>/contrib/xml2</> supports <acronym>XSLT</> (Extensible
-      Stylesheet Language Transformation).
-     </para>
-    </listitem>
-   </varlistentry>
-
-   <varlistentry>
-    <term>XML to SQL Mapping</term>
-    <listitem>
-
-     <para>
-      This involves converting <acronym>XML</> data to and from
-      relational structures. <productname>PostgreSQL</> has no internal
-      support for such mapping, and relies on external tools to do such
-      conversions.
-     </para>
-    </listitem>
-   </varlistentry>
-   </variablelist>
-
   </sect1>
 
  </chapter>