Index: openacs-4/packages/acs-core-docs/www/xml/developers-guide/tutorial-advanced.xml
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-core-docs/www/xml/developers-guide/tutorial-advanced.xml,v
diff -u -r1.43 -r1.44
--- openacs-4/packages/acs-core-docs/www/xml/developers-guide/tutorial-advanced.xml	1 Dec 2004 19:35:40 -0000	1.43
+++ openacs-4/packages/acs-core-docs/www/xml/developers-guide/tutorial-advanced.xml	13 Jan 2005 13:55:16 -0000	1.44
@@ -1583,7 +1583,89 @@
       will be taken care of.</para>
   </sect1>
 
+  <sect1 id="tutorial-second-database">
+    <title>Connect to a second database</title>
+    <para>It is possible to use the OpenACS TCL database API with
+    other databases.  In this example, the OpenACS site uses a
+    PostGre database, and accesses another PostGre database called
+    legacy.</para>
+    <orderedlist>
+      <listitem>
+        <para>Modify config.tcl to accomodate the legacy database, and to
+        ensure that the legacy database is not used for standard
+        OpenACS queries:</para>
+        <programlisting>ns_section ns/db/pools
+ns_param   pool1              "Pool 1"
+ns_param   pool2              "Pool 2"
+ns_param   pool3              "Pool 3"
+ns_param   legacy             "Legacy"
 
+ns_section ns/db/pool/pool1
+<emphasis>#Unchanged from default</emphasis>
+ns_param   maxidle            1000000000
+ns_param   maxopen            1000000000
+ns_param   connections        5
+ns_param   verbose            $debug
+ns_param   extendedtableinfo  true
+ns_param   logsqlerrors       $debug
+if { $database == "oracle" } {
+    ns_param   driver             ora8
+    ns_param   datasource         {}
+    ns_param   user               $db_name
+    ns_param   password           $db_password
+} else {
+    ns_param   driver             postgres
+    ns_param   datasource         ${db_host}:${db_port}:${db_name}
+    ns_param   user               $db_user
+    ns_param   password           ""
+}
+
+ns_section ns/db/pool/pool2
+<emphasis>#Unchanged from default, removed for clarity</emphasis>
+
+ns_section ns/db/pool/pool3
+<emphasis>#Unchanged from default, removed for clarity</emphasis>
+
+ns_section ns/db/pool/legacy
+ns_param   maxidle            1000000000
+ns_param   maxopen            1000000000
+ns_param   connections        5
+ns_param   verbose            $debug
+ns_param   extendedtableinfo  true
+ns_param   logsqlerrors       $debug
+ns_param   driver             postgres
+ns_param   datasource         ${db_host}:${db_port}:legacy_db
+ns_param   user               legacy_user
+ns_param   password           legacy_password
+
+
+ns_section ns/server/${server}/db
+ns_param   pools              *
+ns_param   defaultpool        pool1
+
+ns_section ns/server/${server}/acs/database
+ns_param database_names [list main legacy]
+ns_param pools_main [list pool1 pool2 pool3]
+ns_param pools_legacy [list legacy]</programlisting>
+      </listitem>
+      <listitem>
+        <para>To use the legacy database, use the
+          <computeroutput>-dbn</computeroutput> flag for any of the
+          <computeroutput>db_</computeroutput> API calls.  For
+          example, suppose there is a table called "foo" in the legacy
+          system, with a field "bar".  List "bar" for all records with
+          this tcl file:</para>
+        <programlisting>db_foreach -dbn legacy get_bar_query {
+  select bar from foo
+  limit 10
+} {
+  ns_write "&lt;br/&gt;$bar"
+}</programlisting>
+
+      </listitem>
+    </orderedlist>
+  </sect1>
+
   <sect1 id="tutorial-future-topics">
   <title>Future Topics</title>
     <itemizedlist>