CI_DB_active_record::select PHP Method

    function select($select = '*', $escape = NULL)
    {
        // Set the global value if this was sepecified
        if (is_bool($escape)) {
            $this->_protect_identifiers = $escape;
        }
        if (is_string($select)) {
            $select = explode(',', $select);
        }
        foreach ($select as $val) {
            $val = trim($val);
            if ($val != '') {
                $this->ar_select[] = $val;
                if ($this->ar_caching === TRUE) {
                    $this->ar_cache_select[] = $val;
                    $this->ar_cache_exists[] = 'select';
                }
            }
        }
        return $this;
    }

 public function setup_order(CI_DB_active_record $db)
 {
     $db->join('annotation2scope AS order_annotation2scope', 'order_annotation2scope.annotation_id = annotation.annotation_id');
     $db->join('scope AS order_scope', 'order_scope.scope_id = order_annotation2scope.scope_id');
     if ($this->desc === TRUE) {
         $db->select('order_scope.to_index');
         $db->order_by('order_scope.to_index', $this->get_direction());
     } else {
         $db->select('order_scope.from_index');
         $db->order_by('order_scope.from_index');
     }
     return $db;
 }