本文為英文版的機器翻譯版本，如內容有任何歧義或不一致之處，概以英文版為準。 # 步驟 6：檢視文件的修訂歷史記錄 **重要** 支援終止通知：現有客戶將可以使用 Amazon QLDB，直到 07/31/2025 的支援結束為止。如需詳細資訊，請參閱[將 Amazon QLDB Ledger 遷移至 Amazon Aurora PostgreSQL](https://aws.amazon.com/blogs/database/migrate-an-amazon-qldb-ledger-to-amazon-aurora-postgresql/)。 在上一個步驟中修改車輛的註冊資料後，您可以查詢其所有已註冊擁有者的歷史記錄，以及任何其他更新的欄位。在此步驟中，您會查詢 `vehicle-registration` 分類帳中`VehicleRegistration`資料表中文件的修訂歷史記錄。 **檢視修訂歷史記錄** 1. 使用下列程式 (`query_history.py`) 查詢具有 VIN `VehicleRegistration`的文件修訂歷史記錄`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.') ``` ------ **注意** 您可以在下列語法[歷史記錄函數](working.history.md#working.history.function)中查詢內建 來檢視文件的修訂歷史記錄。 ``` SELECT * FROM history( table_name [, `start-time` [, `end-time` ] ] ) AS h [ WHERE h.metadata.id = 'id' ] ``` *開始時間*和*結束時間*皆為選用。它們是 Amazon Ion 常值，可以用反引號表示 (``...``)。如需進一步了解，請參閱 [在 Amazon QLDB 中使用 PartiQL 查詢離子](ql-reference.query.md)。 最佳實務是，使用日期範圍 *（開始時間*和*結束時間*) 和文件 ID () 來限定歷史記錄查詢`metadata.id`。QLDB 會在交易中處理`SELECT`查詢，這些查詢受到[交易逾時限制](limits.md#limits.fixed)的限制。 QLDB 歷史記錄會依文件 ID 編製索引，此時您無法建立其他歷史記錄索引。包含開始時間和結束時間的歷史記錄查詢可受益於日期範圍資格。 1. 若要執行程式，請輸入下列命令。 ``` python query_history.py ``` 若要以密碼編譯方式驗證 `vehicle-registration` 分類帳中的文件修訂，請繼續 [步驟 7：驗證分類帳中的文件](getting-started.python.step-7.md)。