class Passport extends Document private number null public passport_id

class Passport extends Document {

    private $number = null;
    public $passport_id = null;

    public function setDocumentNumber($number) {
        $this->number = $number;
    }

    public function save() {
        $db = Database::getInstance();
        $query = "INSERT INTO passports ('name', 'birth_date') VALUES ($this->viza_data) RETURNING id;";
        if ($result = pg_query($db, $query)) {
            $db->close();
            $this->passport_id = $result;
            return true;
        }
        return false;
    }

}


class ForeignPassport extends Passport {

    private $viza_data = array();

    public function addVizaData(array $data) {
        $data['passport_id'] = parent::$passport_id;
        $this->viza_data = array_merge($data, $this->viza_data);
    }

    public function save() {
        $db = Database::getInstance();
        $query = "INSERT INTO foreign_passports ('passport_id', 'country', 'date') VALUES ($this->viza_data)";
        if ($result = pg_query($db, $query)) {
            $db->close();
            return true;
        }
        return false;
    }

}