Le traduzioni sono generate tramite traduzione automatica. In caso di conflitto tra il contenuto di una traduzione e la versione originale in Inglese, quest'ultima prevarrà. # Fase 6: Visualizzare la cronologia delle revisioni di un documento **Importante** Avviso di fine del supporto: i clienti esistenti potranno utilizzare Amazon QLDB fino alla fine del supporto, il 31/07/2025. Per ulteriori dettagli, consulta [Migrare un registro Amazon QLDB su Amazon Aurora PostgreSQL](https://aws.amazon.com/blogs/database/migrate-an-amazon-qldb-ledger-to-amazon-aurora-postgresql/). Dopo aver modificato i dati di immatricolazione di un veicolo nel passaggio precedente, puoi interrogare la cronologia di tutti i proprietari registrati e qualsiasi altro campo aggiornato. In questo passaggio, esegui una query sulla cronologia delle revisioni di un documento nella `VehicleRegistration` tabella del registro. `vehicle-registration` **Per visualizzare la cronologia delle revisioni** 1. Utilizzate il seguente programma (`query_history.py`) per interrogare la cronologia delle revisioni del `VehicleRegistration` documento con 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** È possibile visualizzare la cronologia delle revisioni di un documento interrogando la sintassi incorporata [Funzione di cronologia](working.history.md#working.history.function) nella seguente sintassi. ``` SELECT * FROM history( table_name [, `start-time` [, `end-time` ] ] ) AS h [ WHERE h.metadata.id = 'id' ] ``` L'*ora di inizio* e l'ora di *fine* sono entrambe opzionali. Sono valori letterali di Amazon Ion che possono essere indicati con backticks (). ``...`` Per ulteriori informazioni, consulta [Interrogazione di Ion con PartiQL in Amazon QLDB](ql-reference.query.md). Come best practice, qualifica una query cronologica con un intervallo di date (ora di *inizio e ora di fine) e un* *ID del documento ()*. `metadata.id` [QLDB `SELECT` elabora le query nelle transazioni, che sono soggette a un limite di timeout delle transazioni.](limits.md#limits.fixed) La cronologia QLDB è indicizzata in base all'ID del documento e al momento non è possibile creare indici di cronologia aggiuntivi. Le interrogazioni cronologiche che includono l'ora di inizio e l'ora di fine ottengono il vantaggio della qualificazione per intervalli di date. 1. Per eseguire il programma, immetti il comando seguente: ``` python query_history.py ``` Per verificare crittograficamente una revisione di un documento nel registro, procedi a. `vehicle-registration` [Fase 7: Verificare un documento in un libro mastro](getting-started.python.step-7.md)