Paso 6: ver el historial de revisiones de un documento

Tras modificar los datos de registro de un vehículo en el paso anterior, puede consultar el historial de todos sus propietarios registrados y cualquier otro campo actualizado. En este paso, consulta el historial de revisiones de un documento de la tabla VehicleRegistration del libro mayor vehicle-registration.

Para ver el historial de revisiones

Utilice el siguiente programa (query_history.py) para consultar el historial de revisiones del documento VehicleRegistration con el VIN 1N4AL11D75C109151.

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.')

nota

Puede ver el historial de revisiones de un documento consultando la Función de historial integrada en la siguiente sintaxis.
```
SELECT * FROM history( table_name [, `start-time` [, `end-time` ] ] ) AS h
[ WHERE h.metadata.id = 'id' ]
```
Tanto la hora de inicio como la hora de finalización son opcionales. Son valores literales de Amazon Ion que se pueden indicar con acentos graves (`...`). Para obtener más información, consulte Consulta de Ion con PartiQL en Amazon QLDB.
Como práctica recomendada, califique una consulta de historial con un intervalo de fechas (hora de inicio y hora de finalización) y un identificador de documento (metadata.id). QLDB procesa las consultas SELECT en las transacciones, que están sujetas a un límite de tiempo de espera de las transacciones.

El historial de QLDB se indexa por ID de documento y no se pueden crear índices de historial adicionales en este momento. Las consultas de historial que incluyen una hora de inicio y una hora de finalización se benefician de la calificación por intervalo de fechas.

Para ejecutar el programa, introduzca el siguiente comando.
```
python query_history.py
```

Para verificar criptográficamente la revisión de un documento en el libro mayor vehicle-registration, continúe con Paso 7: verificar un documento en un libro mayor.

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Convenciones del documento

Paso 5: modificar los documentos

Paso 7: verificar un documento