public function getIndexes( $oid )
    {

        // load primary keys
        $query = new Query(
            "SELECT string_to_array( indkey::text, ' ') AS keys, * FROM pg_index WHERE indrelid = %oid:int%",
            array( 'oid' => $this->get('oid') )
        );

        $indexes = $this->db->query( $query )->fetch(Result::TYPE_DETECT);

        foreach( $this->indexes as &$index ) {

            $index['columns'] = array();

            foreach( $index['keys'] as $columnIndex ) {
                $index['columns'][] = sprintf(
                    '%s.%s',
                    $oid,
                    $columnIndex
                );
            }

        }

        return $indexes;

    }