Langkah 6: Lihat riwayat revisi dokumen - Amazon Quantum Ledger Database (Amazon QLDB)

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Langkah 6: Lihat riwayat revisi dokumen

Setelah memodifikasi data pendaftaran untuk kendaraan pada langkah sebelumnya, Anda dapat menanyakan riwayat semua pemilik terdaftar dan bidang terbaru lainnya. Pada langkah ini, Anda menanyakan riwayat revisi dokumen dalamVehicleRegistration tabel divehicle-registration buku besar Anda.

Untuk melihat riwayat revisi

  1. Gunakan program berikut (query_history.py) untuk query sejarah revisiVehicleRegistration dokumen dengan VIN1N4AL11D75C109151.

    3.x
    # Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
# SPDX-License-Identifier: MIT-0
#
# Permission is hereby granted, free of charge, to any person obtaining a copy of this
# software and associated documentation files (the "Software"), to deal in the Software
# without restriction, including without limitation the rights to use, copy, modify,
# merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
# INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
# PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#
# This code expects that you have AWS credentials setup per:
# https://boto3.amazonaws.com/v1/documentation/api/latest/guide/quickstart.html
from datetime import datetime, timedelta
from logging import basicConfig, getLogger, INFO

from pyqldbsamples.model.sample_data import print_result, get_document_ids, SampleData
from pyqldbsamples.constants import Constants
from pyqldbsamples.connect_to_ledger import create_qldb_driver

logger = getLogger(__name__)
basicConfig(level=INFO)


def format_date_time(date_time):
    """
    Format the given date time to a string.

    :type date_time: :py:class:`datetime.datetime`
    :param date_time: The date time to format.

    :rtype: str
    :return: The formatted date time.
    """
    return date_time.strftime('`%Y-%m-%dT%H:%M:%S.%fZ`')


def previous_primary_owners(driver, vin):
    """
    Find previous primary owners for the given VIN in a single transaction.
    In this example, query the `VehicleRegistration` history table to find all previous primary owners for a VIN.

    :type driver: :py:class:`pyqldb.driver.qldb_driver.QldbDriver`
    :param driver: An instance of the QldbDriver class.

    :type vin: str
    :param vin: VIN to find previous primary owners for.
    """
    person_ids = driver.execute_lambda(lambda executor: get_document_ids(executor,
                                                                         Constants.VEHICLE_REGISTRATION_TABLE_NAME,
                                                                         'VIN', vin))

    todays_date = datetime.utcnow() - timedelta(seconds=1)
    three_months_ago = todays_date - timedelta(days=90)
    query = 'SELECT data.Owners.PrimaryOwner, metadata.version FROM history({}, {}, {}) AS h WHERE h.metadata.id = ?'.\
        format(Constants.VEHICLE_REGISTRATION_TABLE_NAME, format_date_time(three_months_ago),
               format_date_time(todays_date))

    for ids in person_ids:
        logger.info("Querying the 'VehicleRegistration' table's history using VIN: {}.".format(vin))
        cursor = driver.execute_lambda(lambda executor: executor.execute_statement(query, ids))
        if not (print_result(cursor)) > 0:
            logger.info('No modification history found within the given time frame for document ID: {}'.format(ids))


def main(ledger_name=Constants.LEDGER_NAME):
    """
    Query a table's history for a particular set of documents.
    """
    try:
        with create_qldb_driver(ledger_name) as driver:
            vin = SampleData.VEHICLE_REGISTRATION[0]['VIN']
            previous_primary_owners(driver, vin)
            logger.info('Successfully queried history.')
    except Exception as e:
        logger.exception('Unable to query history to find previous owners.')
        raise e


if __name__ == '__main__':
    main()
    2.x
    # Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
# SPDX-License-Identifier: MIT-0
#
# Permission is hereby granted, free of charge, to any person obtaining a copy of this
# software and associated documentation files (the "Software"), to deal in the Software
# without restriction, including without limitation the rights to use, copy, modify,
# merge, publish, distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
# INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
# PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#
# This code expects that you have AWS credentials setup per:
# https://boto3.amazonaws.com/v1/documentation/api/latest/guide/quickstart.html
from datetime import datetime, timedelta
from logging import basicConfig, getLogger, INFO

from pyqldbsamples.model.sample_data import print_result, get_document_ids, SampleData
from pyqldbsamples.constants import Constants
from pyqldbsamples.connect_to_ledger import create_qldb_session

logger = getLogger(__name__)
basicConfig(level=INFO)


def format_date_time(date_time):
    """
    Format the given date time to a string.

    :type date_time: :py:class:`datetime.datetime`
    :param date_time: The date time to format.

    :rtype: str
    :return: The formatted date time.
    """
    return date_time.strftime('`%Y-%m-%dT%H:%M:%S.%fZ`')


def previous_primary_owners(transaction_executor, vin):
    """
    Find previous primary owners for the given VIN in a single transaction.
    In this example, query the `VehicleRegistration` history table to find all previous primary owners for a VIN.

    :type transaction_executor: :py:class:`pyqldb.execution.executor.Executor`
    :param transaction_executor: An Executor object allowing for execution of statements within a transaction.

    :type vin: str
    :param vin: VIN to find previous primary owners for.
    """
    person_ids = get_document_ids(transaction_executor, Constants.VEHICLE_REGISTRATION_TABLE_NAME, 'VIN', vin)

    todays_date = datetime.utcnow() - timedelta(seconds=1)
    three_months_ago = todays_date - timedelta(days=90)
    query = 'SELECT data.Owners.PrimaryOwner, metadata.version FROM history({}, {}, {}) AS h WHERE h.metadata.id = ?'.\
        format(Constants.VEHICLE_REGISTRATION_TABLE_NAME, format_date_time(three_months_ago),
               format_date_time(todays_date))

    for ids in person_ids:
        logger.info("Querying the 'VehicleRegistration' table's history using VIN: {}.".format(vin))
        cursor = transaction_executor.execute_statement(query, ids)
        if not (print_result(cursor)) > 0:
            logger.info('No modification history found within the given time frame for document ID: {}'.format(ids))


if __name__ == '__main__':
    """
    Query a table's history for a particular set of documents.
    """
    try:
        with create_qldb_session() as session:
            vin = SampleData.VEHICLE_REGISTRATION[0]['VIN']
            session.execute_lambda(lambda lambda_executor: previous_primary_owners(lambda_executor, vin),
                                   lambda retry_attempt: logger.info('Retrying due to OCC conflict...'))
            logger.info('Successfully queried history.')
    except Exception:
        logger.exception('Unable to query history to find previous owners.')
    catatan

    • Anda dapat melihat riwayat revisi dokumen dengan menanyakan built-inFungsi Riwayat dalam sintaks berikut.

      SELECT * FROM history( table_name [, `start-time` [, `end-time` ] ] ) AS h
[ WHERE h.metadata.id = 'id' ]

    • Start-time dan end-time keduanya opsional. Mereka adalah nilai literal Amazon Ion yang dapat dilambangkan dengan backticks (`...`). Untuk mempelajari selengkapnya, lihat Menanyakan Ion dengan PartiQL di Amazon QLDB.

    • Sebagai praktik terbaik, kualifikasi kueri riwayat dengan rentang tanggal (start-time dan end-time) dan ID dokumen (metadata.id). QLDB memprosesSELECT kueri dalam transaksi, yang tunduk pada batas batas waktu transaksi.

      Riwayat QLDB diindeks oleh ID dokumen, dan Anda tidak dapat membuat indeks riwayat tambahan saat ini. Kueri riwayat yang menyertakan waktu mulai dan waktu akhir mendapatkan manfaat kualifikasi rentang tanggal.

  2. Untuk menjalankan program, masukkan perintah berikut.

    python query_history.py

Untuk memverifikasi revisi dokumen secara kriptografis divehicle-registration buku besar, lanjutkan keLangkah 7: Verifikasi dokumen di buku besar.