update room number field to be an integer

booking.rooms_admin.inc

@@ -425,6 +425,18 @@ function booking_rooms_definition_form($node, &$form_state, $create, $room_id =
 	}
 }
 
+/**
+ * Validate the form for adding room definitions
+ */
+function booking_rooms_definition_form_validate($form, $form_state) {
+	//make sure room number is numerical
+	$values = $form_state['input'];
+
+	if (! is_numeric($values['booking_room_number'])) {
+		form_set_error('booking_room_number', t('Room number must be numeric. If you need to use a more descriptive label, please use the room label field.'));
+	}
+}
+
 /**
  * Process the form for adding room definitions
  */