- support for 3rd party extension tables

db/schema/ser.xml

@@ -76,6 +76,14 @@
 
     <xi:include href="i18n.xml"/>
 
+    <!-- Include extra definitions if found, it is not
+         an error if they are not present, although it
+         would produce a warning
+      -->
+    <xi:include href="extra.xml" xpointer="xpointer(data/table)">
+	<xi:fallback/>
+    </xi:include>
+
     <!-- User with read/write access -->
     <user>
 	<username>ser</username>