/**
  * Return array containing information about all storage location hierarchies, including their root_id's
  */
 public function getHierarchyList($pb_dummy = false)
 {
     $vn_root_id = $this->getHierarchyRootID();
     $t_root = new ca_storage_locations($vn_root_id);
     $qr_children = $t_root->getHierarchyChildrenAsQuery();
     $va_preferred_labels = $t_root->getPreferredLabels(null, false);
     return array(array('location_id' => $vn_id = $t_root->getPrimaryKey(), 'item_id' => $vn_id, 'name' => _t('Storage locations'), 'children' => $qr_children->numRows(), 'has_children' => $qr_children->numRows() ? true : false));
 }