public function update($table, $records, $where = array(), $limit = 0) {
        $this->sql = sprintf("UPDATE `%s` SET %s %s%s;", SafeString::makeSafe($table), $this->fields($records), $this->where($where), $this->limit($limit));
        $this->executeQuery(false);
        return $this->numRows() ? true : false;
    }