public function orderBy($column, $how = 'ASC')
    {
        if (!array_key_exists('order_by', $this->query)) {
            $this->query['order_by'] = array();
        }

        // Multiple?
        if (is_array($column)) {
            foreach ($column as $col => $how) {
                $this->orderBy($col, $how);
            }
        } else {
            $this->query['order_by'][] = $this->columnName($column) . " {$how}";
        }
        return $this;
    }