<!-- Module User's Guide -->

<chapter>
	
	<title>&adminguide;</title>
	
	<section id="overview" xreflabel="Overview">
	<title>Overview</title>
	<para>
		The Perl Virtual Database (VDB) provides a virtualization framework
		for &osips;'s database access. It does not handle a particular
		database engine itself but lets the user relay database requests
		to arbitrary Perl functions.
	</para>
	<para>
		This module cannot be used "out of the box". The user has to supply
		functionality dedicated to the client module. See below for options.
	</para>
	<para>
		The module can be used in all current &osips; modules that need
		database access. Relaying of insert, update, query and delete
		operations is supported.
	</para>
	<para>
		Modules can be configured to use the db_perlvdb module as
		database backend using the db_url_parameter:
	</para>
	<programlisting>
modparam("acc", "db_url", "perlvdb:OpenSIPS::VDB::Adapter::AccountingSIPtrace")
</programlisting>
	<para>
		This configuration options tells acc module that it should use the
		db_perlvdb module which will in turn use the Perl class
		OpenSIPS::VDB::Adapter::AccountingSIPtrace
		to relay the database requests.
	</para>
	</section>

	<section id="dependencies" xreflabel="Dependencies">
	<title>Dependencies</title>
	<section>
		<title>&osips; Modules</title>
		<para>
		The following  modules must be loaded before this module:
			<itemizedlist>
			<listitem>
				<para><emphasis>perl</emphasis> -- Perl module</para>
			</listitem>
			</itemizedlist>
		</para>
	</section>
	<section>
		<title>External Libraries or Applications</title>
		<para>
		The following libraries or applications must be installed before running
		&osips; with this module loaded:
			<itemizedlist>
			<listitem>
			<para>
				<emphasis>None</emphasis> (Besides the ones mentioned in the perl
				module documentation).
			</para>
			</listitem>
			</itemizedlist>
		</para>
	</section>
	</section>

	<section id="exported_parameters" xreflabel="Exported Parameters">
	<title>Exported Parameters</title>
		<para>
			<emphasis>None</emphasis>.
		</para>
	</section>

	<section id="exported_functions" xreflabel="exported_functions">
	<title>Exported Functions</title>
		<para>
			<emphasis>None</emphasis>.
		</para>
	</section>

</chapter>

