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# Tutorial su Amazon QLDB Python
<a name="getting-started.python.tutorial"></a>

**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/).

In questa implementazione dell'applicazione di esempio del tutorial, utilizzi il driver Amazon QLDB con AWS SDK per Python (Boto3) per creare un registro QLDB e compilarlo con dati di esempio.

Mentre segui questo tutorial, puoi fare riferimento al client di [basso livello QLDB](https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/qldb.html) nell'*SDK for Python (Boto3) API Reference per AWS le* operazioni dell'API di gestione. Per le operazioni sui dati transazionali, puoi fare riferimento al [QLDB Driver for](https://amazon-qldb-driver-python.readthedocs.io/en/stable/) Python API Reference.

**Nota**  
Ove applicabile, alcuni passaggi del tutorial contengono comandi o esempi di codice diversi per ogni versione principale supportata del driver QLDB per Python.

**Topics**
+ [Installazione dell'applicazione di esempio Amazon QLDB Python](sample-app.python.md)
+ [Fase 1: Creare un nuovo registro](getting-started.python.step-1.md)
+ [Passaggio 2: verifica la connettività al registro](getting-started.python.step-2.md)
+ [Passaggio 3: Creare tabelle, indici e dati di esempio](getting-started.python.step-3.md)
+ [Passaggio 4: interrogare le tabelle in un libro mastro](getting-started.python.step-4.md)
+ [Fase 5: Modificare i documenti in un libro mastro](getting-started.python.step-5.md)
+ [Fase 6: Visualizzare la cronologia delle revisioni di un documento](getting-started.python.step-6.md)
+ [Fase 7: Verificare un documento in un libro mastro](getting-started.python.step-7.md)
+ [Passaggio 8 (opzionale): Pulisci le risorse](getting-started.python.step-8.md)

# Installazione dell'applicazione di esempio Amazon QLDB Python
<a name="sample-app.python"></a>

**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/).

Questa sezione descrive come installare ed eseguire l'applicazione di esempio Amazon QLDB fornita per il step-by-step tutorial Python. Il caso d'uso di questa applicazione di esempio è un database del Dipartimento dei veicoli a motore (DMV) che tiene traccia delle informazioni storiche complete sulle immatricolazioni dei veicoli.

[L'applicazione di esempio DMV per Python è open source nel repository aws-samples/ -python. GitHub amazon-qldb-dmv-sample](https://github.com/aws-samples/amazon-qldb-dmv-sample-python)

## Prerequisiti
<a name="sample-app.python.prereqs"></a>

Prima di iniziare, assicurati di completare il driver QLDB per Python. [Prerequisiti](getting-started.python.md#getting-started.python.prereqs) Ciò include l'installazione di Python e le seguenti operazioni:

1. Iscriviti a. AWS

1. Crea un utente con le autorizzazioni QLDB appropriate.

1. Concedi l'accesso programmatico per lo sviluppo.

Per completare tutti i passaggi di questo tutorial, è necessario l'accesso amministrativo completo alla risorsa di registro tramite l'API QLDB.

## Installazione
<a name="sample-app.python.install"></a>

**Per installare l'applicazione di esempio**

1. Immettete il seguente `pip` comando per clonare e installare l'applicazione di esempio da GitHub.

------
#### [ 3.x ]

   ```
   pip install git+https://github.com/aws-samples/amazon-qldb-dmv-sample-python.git
   ```

------
#### [ 2.x ]

   ```
   pip install git+https://github.com/aws-samples/amazon-qldb-dmv-sample-python.git@v1.0.0
   ```

------

   L'applicazione di esempio racchiude il codice sorgente completo di questo tutorial e le sue dipendenze, inclusi il driver Python e il. [AWS SDK per Python (Boto3)](https://aws.amazon.com/sdk-for-python)

1. Prima di iniziare a eseguire il codice dalla riga di comando, spostate la directory di lavoro corrente nella posizione in cui è installato il `pyqldbsamples` pacchetto. Inserire il seguente comando.

   ```
   cd $(python -c "import pyqldbsamples; print(pyqldbsamples.__path__[0])")
   ```

1. Procedi con [Fase 1: Creare un nuovo registro](getting-started.python.step-1.md) l'avvio del tutorial e la creazione di un libro mastro.

# Fase 1: Creare un nuovo registro
<a name="getting-started.python.step-1"></a>

**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/).

In questo passaggio, crei un nuovo registro Amazon QLDB denominato. `vehicle-registration`

**Per creare un nuovo registro**

1. Esamina il seguente file (`constants.py`), che contiene valori costanti utilizzati da tutti gli altri programmi di questo tutorial.

   ```
   # 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.
   
   
   class Constants:
       """
       Constant values used throughout this tutorial.
       """
       LEDGER_NAME = "vehicle-registration"
   
       VEHICLE_REGISTRATION_TABLE_NAME = "VehicleRegistration"
       VEHICLE_TABLE_NAME = "Vehicle"
       PERSON_TABLE_NAME = "Person"
       DRIVERS_LICENSE_TABLE_NAME = "DriversLicense"
   
       LICENSE_NUMBER_INDEX_NAME = "LicenseNumber"
       GOV_ID_INDEX_NAME = "GovId"
       VEHICLE_VIN_INDEX_NAME = "VIN"
       LICENSE_PLATE_NUMBER_INDEX_NAME = "LicensePlateNumber"
       PERSON_ID_INDEX_NAME = "PersonId"
   
       JOURNAL_EXPORT_S3_BUCKET_NAME_PREFIX = "qldb-tutorial-journal-export"
       USER_TABLES = "information_schema.user_tables"
       S3_BUCKET_ARN_TEMPLATE = "arn:aws:s3:::"
       LEDGER_NAME_WITH_TAGS = "tags"
   
       RETRY_LIMIT = 4
   ```

1. Utilizzate il seguente programma (`create_ledger.py`) per creare un registro denominato`vehicle-registration`.

   ```
   # 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 logging import basicConfig, getLogger, INFO
   from time import sleep
   
   from boto3 import client
   
   from pyqldbsamples.constants import Constants
   
   logger = getLogger(__name__)
   basicConfig(level=INFO)
   qldb_client = client('qldb')
   
   LEDGER_CREATION_POLL_PERIOD_SEC = 10
   ACTIVE_STATE = "ACTIVE"
   
   
   def create_ledger(name):
       """
       Create a new ledger with the specified name.
   
       :type name: str
       :param name: Name for the ledger to be created.
   
       :rtype: dict
       :return: Result from the request.
       """
       logger.info("Let's create the ledger named: {}...".format(name))
       result = qldb_client.create_ledger(Name=name, PermissionsMode='ALLOW_ALL')
       logger.info('Success. Ledger state: {}.'.format(result.get('State')))
       return result
   
   
   def wait_for_active(name):
       """
       Wait for the newly created ledger to become active.
   
       :type name: str
       :param name: The ledger to check on.
   
       :rtype: dict
       :return: Result from the request.
       """
       logger.info('Waiting for ledger to become active...')
       while True:
           result = qldb_client.describe_ledger(Name=name)
           if result.get('State') == ACTIVE_STATE:
               logger.info('Success. Ledger is active and ready to use.')
               return result
           logger.info('The ledger is still creating. Please wait...')
           sleep(LEDGER_CREATION_POLL_PERIOD_SEC)
   
   
   def main(ledger_name=Constants.LEDGER_NAME):
       """
       Create a ledger and wait for it to be active.
       """
       try:
           create_ledger(ledger_name)
           wait_for_active(ledger_name)
       except Exception as e:
           logger.exception('Unable to create the ledger!')
           raise e
   
   
   if __name__ == '__main__':
       main()
   ```
**Nota**  
Nella `create_ledger` chiamata, è necessario specificare un nome di registro e una modalità di autorizzazione. Ti consigliamo di utilizzare la modalità `STANDARD` autorizzazioni per massimizzare la sicurezza dei dati del registro.
Quando si crea un registro, la *protezione da eliminazione* è abilitata per impostazione predefinita. Questa è una funzionalità di QLDB che impedisce l'eliminazione dei registri da parte di qualsiasi utente. Hai la possibilità di disabilitare la protezione da eliminazione durante la creazione del registro utilizzando l'API QLDB o il (). AWS Command Line Interface AWS CLI
Facoltativamente, puoi anche specificare i tag da allegare al tuo libro mastro.

1. Per eseguire il programma, immetti il comando seguente:

   ```
   python create_ledger.py
   ```

Per verificare la connessione al nuovo registro, procedi a. [Passaggio 2: verifica la connettività al registro](getting-started.python.step-2.md)

# Passaggio 2: verifica la connettività al registro
<a name="getting-started.python.step-2"></a>

**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/).

In questo passaggio, verifichi di poterti connettere al `vehicle-registration` registro in Amazon QLDB utilizzando l'endpoint API dei dati transazionali.

**Per testare la connettività al registro**

1. Utilizzate il seguente programma (`connect_to_ledger.py`) per creare una connessione di sessione dati al `vehicle-registration` registro.

------
#### [ 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 logging import basicConfig, getLogger, INFO
   
   from botocore.exceptions import ClientError
   
   from pyqldb.driver.qldb_driver import QldbDriver
   from pyqldbsamples.constants import Constants
   
   logger = getLogger(__name__)
   basicConfig(level=INFO)
   
   
   def create_qldb_driver(ledger_name=Constants.LEDGER_NAME, region_name=None, endpoint_url=None, boto3_session=None):
       """
       Create a QLDB driver for executing transactions.
   
       :type ledger_name: str
       :param ledger_name: The QLDB ledger name.
   
       :type region_name: str
       :param region_name: See [1].
   
       :type endpoint_url: str
       :param endpoint_url: See [1].
   
       :type boto3_session: :py:class:`boto3.session.Session`
       :param boto3_session: The boto3 session to create the client with (see [1]).
   
       :rtype: :py:class:`pyqldb.driver.qldb_driver.QldbDriver`
       :return: A QLDB driver object.
   
       [1]: `Boto3 Session.client Reference <https://boto3.amazonaws.com/v1/documentation/api/latest/reference/core/session.html#boto3.session.Session.client>`.
       """
       qldb_driver = QldbDriver(ledger_name=ledger_name, region_name=region_name, endpoint_url=endpoint_url,
                                boto3_session=boto3_session)
       return qldb_driver
   
   
   def main(ledger_name=Constants.LEDGER_NAME):
       """
       Connect to a given ledger using default settings.
       """
       try:
           with create_qldb_driver(ledger_name) as driver:
               logger.info('Listing table names ')
               for table in driver.list_tables():
                   logger.info(table)
       except ClientError as ce:
           logger.exception('Unable to list tables.')
           raise ce
   
   
   if __name__ == '__main__':
       main()
   ```

**Nota**  
Per eseguire transazioni di dati sul registro, è necessario creare un oggetto driver QLDB per connettersi a un registro specifico. Si tratta di un oggetto client diverso dall'`qldb_client`oggetto utilizzato nel passaggio precedente per creare il registro. Quel client precedente viene utilizzato solo per eseguire le operazioni dell'API di gestione elencate in. [Riferimento all'API Amazon QLDB](api-reference.md)
È necessario specificare un nome contabile quando si crea questo oggetto driver.

------
#### [ 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 logging import basicConfig, getLogger, INFO
   
   from botocore.exceptions import ClientError
   
   from pyqldb.driver.pooled_qldb_driver import PooledQldbDriver
   from pyqldbsamples.constants import Constants
   
   logger = getLogger(__name__)
   basicConfig(level=INFO)
   
   
   def create_qldb_driver(ledger_name=Constants.LEDGER_NAME, region_name=None, endpoint_url=None, boto3_session=None):
       """
       Create a QLDB driver for creating sessions.
   
       :type ledger_name: str
       :param ledger_name: The QLDB ledger name.
   
       :type region_name: str
       :param region_name: See [1].
   
       :type endpoint_url: str
       :param endpoint_url: See [1].
   
       :type boto3_session: :py:class:`boto3.session.Session`
       :param boto3_session: The boto3 session to create the client with (see [1]).
   
       :rtype: :py:class:`pyqldb.driver.pooled_qldb_driver.PooledQldbDriver`
       :return: A pooled QLDB driver object.
   
       [1]: `Boto3 Session.client Reference <https://boto3.amazonaws.com/v1/documentation/api/latest/reference/core/session.html#boto3.session.Session.client>`.
       """
       qldb_driver = PooledQldbDriver(ledger_name=ledger_name, region_name=region_name, endpoint_url=endpoint_url,
                                      boto3_session=boto3_session)
       return qldb_driver
   
   
   def create_qldb_session():
       """
       Retrieve a QLDB session object.
   
       :rtype: :py:class:`pyqldb.session.pooled_qldb_session.PooledQldbSession`
       :return: A pooled QLDB session object.
       """
       qldb_session = pooled_qldb_driver.get_session()
       return qldb_session
   
   
   pooled_qldb_driver = create_qldb_driver()
   
   
   if __name__ == '__main__':
       """
       Connect to a session for a given ledger using default settings.
       """
       try:
           qldb_session = create_qldb_session()
           logger.info('Listing table names ')
           for table in qldb_session.list_tables():
               logger.info(table)
       except ClientError:
           logger.exception('Unable to create session.')
   ```

**Nota**  
Per eseguire transazioni di dati sul registro, è necessario creare un oggetto driver QLDB per connettersi a un registro specifico. Si tratta di un oggetto client diverso dall'`qldb_client`oggetto utilizzato nel passaggio precedente per creare il registro. Quel client precedente viene utilizzato solo per eseguire le operazioni dell'API di gestione elencate in. [Riferimento all'API Amazon QLDB](api-reference.md)
Innanzitutto, crea un oggetto driver QLDB in pool. È necessario specificare un nome contabile quando si crea questo driver.
Quindi, è possibile creare sessioni da questo oggetto driver condiviso.

------

1. Per eseguire il programma, immetti il comando seguente:

   ```
   python connect_to_ledger.py
   ```

Per creare tabelle nel `vehicle-registration` registro, procedi a. [Passaggio 3: Creare tabelle, indici e dati di esempio](getting-started.python.step-3.md)

# Passaggio 3: Creare tabelle, indici e dati di esempio
<a name="getting-started.python.step-3"></a>

**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/).

Quando il tuo registro Amazon QLDB è attivo e accetta connessioni, puoi iniziare a creare tabelle per i dati sui veicoli, i loro proprietari e le loro informazioni di immatricolazione. Dopo aver creato le tabelle e gli indici, puoi caricarli con i dati.

In questo passaggio, crei quattro tabelle nel libro mastro: `vehicle-registration`
+ `VehicleRegistration`
+ `Vehicle`
+ `Person`
+ `DriversLicense`

Vengono inoltre creati i seguenti indici.


****  

| Nome tabella | Campo | 
| --- | --- | 
| VehicleRegistration | VIN | 
| VehicleRegistration | LicensePlateNumber | 
| Vehicle | VIN | 
| Person | GovId | 
| DriversLicense | LicenseNumber | 
| DriversLicense | PersonId | 

Quando si inseriscono dati di esempio, si inseriscono innanzitutto i documenti nella tabella. `Person` Quindi, si utilizzano i dati assegnati `id` dal sistema a ciascun `Person` documento per compilare i campi corrispondenti nei documenti e nei documenti appropriati. `VehicleRegistration` `DriversLicense`

**Suggerimento**  
Come procedura ottimale, utilizzate il sistema assegnato a un documento come chiave esterna`id`. Sebbene sia possibile definire campi destinati a essere identificatori univoci (ad esempio, il VIN di un veicolo), il vero identificatore univoco di un documento è il suo. `id` Questo campo è incluso nei metadati del documento, a cui è possibile eseguire una query nella visualizzazione confermata (*la vista* di una tabella definita dal sistema).  
Per ulteriori informazioni sulle viste in QLDB, vedere. [Concetti principali](ledger-structure.md) Per ulteriori informazioni sui metadati, consulta. [Interrogazione dei metadati dei documenti](working.metadata.md)

**Per creare tabelle e indici**

1. Utilizzate il seguente programma (`create_table.py`) per creare le tabelle menzionate in precedenza.

------
#### [ 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 logging import basicConfig, getLogger, INFO
   
   from pyqldbsamples.constants import Constants
   from pyqldbsamples.connect_to_ledger import create_qldb_driver
   
   logger = getLogger(__name__)
   basicConfig(level=INFO)
   
   
   def create_table(driver, table_name):
       """
       Create a table with the specified name.
   
       :type driver: :py:class:`pyqldb.driver.qldb_driver.QldbDriver`
       :param driver: An instance of the QldbDriver class.
   
       :type table_name: str
       :param table_name: Name of the table to create.
   
       :rtype: int
       :return: The number of changes to the database.
       """
       logger.info("Creating the '{}' table...".format(table_name))
       statement = 'CREATE TABLE {}'.format(table_name)
       cursor = driver.execute_lambda(lambda executor: executor.execute_statement(statement))
       logger.info('{} table created successfully.'.format(table_name))
       return len(list(cursor))
   
   
   def main(ledger_name=Constants.LEDGER_NAME):
       """
       Create registrations, vehicles, owners, and licenses tables.
       """
       try:
           with create_qldb_driver(ledger_name) as driver:
               create_table(driver, Constants.DRIVERS_LICENSE_TABLE_NAME)
               create_table(driver, Constants.PERSON_TABLE_NAME)
               create_table(driver, Constants.VEHICLE_TABLE_NAME)
               create_table(driver, Constants.VEHICLE_REGISTRATION_TABLE_NAME)
               logger.info('Tables created successfully.')
       except Exception as e:
           logger.exception('Errors creating tables.')
           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 logging import basicConfig, getLogger, INFO
   
   from pyqldbsamples.constants import Constants
   from pyqldbsamples.connect_to_ledger import create_qldb_session
   
   logger = getLogger(__name__)
   basicConfig(level=INFO)
   
   
   def create_table(transaction_executor, table_name):
       """
       Create a table with the specified name using an Executor object.
   
       :type transaction_executor: :py:class:`pyqldb.execution.executor.Executor`
       :param transaction_executor: An Executor object allowing for execution of statements within a transaction.
   
       :type table_name: str
       :param table_name: Name of the table to create.
   
       :rtype: int
       :return: The number of changes to the database.
       """
       logger.info("Creating the '{}' table...".format(table_name))
       statement = 'CREATE TABLE {}'.format(table_name)
       cursor = transaction_executor.execute_statement(statement)
       logger.info('{} table created successfully.'.format(table_name))
       return len(list(cursor))
   
   
   if __name__ == '__main__':
       """
       Create registrations, vehicles, owners, and licenses tables in a single transaction.
       """
       try:
           with create_qldb_session() as session:
               session.execute_lambda(lambda x: create_table(x, Constants.DRIVERS_LICENSE_TABLE_NAME) and
                                      create_table(x, Constants.PERSON_TABLE_NAME) and
                                      create_table(x, Constants.VEHICLE_TABLE_NAME) and
                                      create_table(x, Constants.VEHICLE_REGISTRATION_TABLE_NAME),
                                      lambda retry_attempt: logger.info('Retrying due to OCC conflict...'))
               logger.info('Tables created successfully.')
       except Exception:
           logger.exception('Errors creating tables.')
   ```

------
**Nota**  
Questo programma dimostra come utilizzare la `execute_lambda` funzione. In questo esempio, esegui più istruzioni `CREATE TABLE` PartiQL con una singola espressione lambda.  
Questa funzione di esecuzione avvia implicitamente una transazione, esegue tutte le istruzioni in lambda e quindi esegue automaticamente il commit della transazione.

1. Per eseguire il programma, immetti il comando seguente:

   ```
   python create_table.py
   ```

1. Utilizzate il seguente programma (`create_index.py`) per creare indici sulle tabelle, come descritto in precedenza.

------
#### [ 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 logging import basicConfig, getLogger, INFO
   
   from pyqldbsamples.constants import Constants
   from pyqldbsamples.connect_to_ledger import create_qldb_driver
   
   logger = getLogger(__name__)
   basicConfig(level=INFO)
   
   
   def create_index(driver, table_name, index_attribute):
       """
       Create an index for a particular table.
   
       :type driver: :py:class:`pyqldb.driver.qldb_driver.QldbDriver`
       :param driver: An instance of the QldbDriver class.
   
       :type table_name: str
       :param table_name: Name of the table to add indexes for.
   
       :type index_attribute: str
       :param index_attribute: Index to create on a single attribute.
   
       :rtype: int
       :return: The number of changes to the database.
       """
       logger.info("Creating index on '{}'...".format(index_attribute))
       statement = 'CREATE INDEX on {} ({})'.format(table_name, index_attribute)
       cursor = driver.execute_lambda(lambda executor: executor.execute_statement(statement))
       return len(list(cursor))
   
   
   def main(ledger_name=Constants.LEDGER_NAME):
       """
       Create indexes on tables in a particular ledger.
       """
       logger.info('Creating indexes on all tables...')
       try:
           with create_qldb_driver(ledger_name) as driver:
               create_index(driver, Constants.PERSON_TABLE_NAME, Constants.GOV_ID_INDEX_NAME)
               create_index(driver, Constants.VEHICLE_TABLE_NAME, Constants.VEHICLE_VIN_INDEX_NAME)
               create_index(driver, Constants.VEHICLE_REGISTRATION_TABLE_NAME, Constants.LICENSE_PLATE_NUMBER_INDEX_NAME)
               create_index(driver, Constants.VEHICLE_REGISTRATION_TABLE_NAME, Constants.VEHICLE_VIN_INDEX_NAME)
               create_index(driver, Constants.DRIVERS_LICENSE_TABLE_NAME, Constants.PERSON_ID_INDEX_NAME)
               create_index(driver, Constants.DRIVERS_LICENSE_TABLE_NAME, Constants.LICENSE_NUMBER_INDEX_NAME)
               logger.info('Indexes created successfully.')
       except Exception as e:
           logger.exception('Unable to create indexes.')
           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 logging import basicConfig, getLogger, INFO
   
   from pyqldbsamples.constants import Constants
   from pyqldbsamples.connect_to_ledger import create_qldb_session
   
   logger = getLogger(__name__)
   basicConfig(level=INFO)
   
   
   def create_index(transaction_executor, table_name, index_attribute):
       """
       Create an index for a particular table.
   
       :type transaction_executor: :py:class:`pyqldb.execution.executor.Executor`
       :param transaction_executor: An Executor object allowing for execution of statements within a transaction.
   
       :type table_name: str
       :param table_name: Name of the table to add indexes for.
   
       :type index_attribute: str
       :param index_attribute: Index to create on a single attribute.
   
       :rtype: int
       :return: The number of changes to the database.
       """
       logger.info("Creating index on '{}'...".format(index_attribute))
       statement = 'CREATE INDEX on {} ({})'.format(table_name, index_attribute)
       cursor = transaction_executor.execute_statement(statement)
       return len(list(cursor))
   
   
   if __name__ == '__main__':
       """
       Create indexes on tables in a particular ledger.
       """
       logger.info('Creating indexes on all tables in a single transaction...')
       try:
           with create_qldb_session() as session:
               session.execute_lambda(lambda x: create_index(x, Constants.PERSON_TABLE_NAME,
                                                             Constants.GOV_ID_INDEX_NAME)
                                      and create_index(x, Constants.VEHICLE_TABLE_NAME,
                                                       Constants.VEHICLE_VIN_INDEX_NAME)
                                      and create_index(x, Constants.VEHICLE_REGISTRATION_TABLE_NAME,
                                                       Constants.LICENSE_PLATE_NUMBER_INDEX_NAME)
                                      and create_index(x, Constants.VEHICLE_REGISTRATION_TABLE_NAME,
                                                       Constants.VEHICLE_VIN_INDEX_NAME)
                                      and create_index(x, Constants.DRIVERS_LICENSE_TABLE_NAME,
                                                       Constants.PERSON_ID_INDEX_NAME)
                                      and create_index(x, Constants.DRIVERS_LICENSE_TABLE_NAME,
                                                       Constants.LICENSE_NUMBER_INDEX_NAME),
                                      lambda retry_attempt: logger.info('Retrying due to OCC conflict...'))
               logger.info('Indexes created successfully.')
       except Exception:
           logger.exception('Unable to create indexes.')
   ```

------

1. Per eseguire il programma, immetti il comando seguente:

   ```
   python create_index.py
   ```

**Per caricare i dati nelle tabelle**

1. Esaminate il seguente file (`sample_data.py`), che rappresenta i dati di esempio che inserite nelle `vehicle-registration` tabelle. Questo file viene inoltre importato dal `amazon.ion` pacchetto per fornire funzioni di supporto che convertono, analizzano e stampano i dati di [Amazon Ion.](ion.md) 

   ```
   # 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.
   from datetime import datetime
   from decimal import Decimal
   from logging import basicConfig, getLogger, INFO
   
   from amazon.ion.simple_types import IonPyBool, IonPyBytes, IonPyDecimal, IonPyDict, IonPyFloat, IonPyInt, IonPyList, \
       IonPyNull, IonPySymbol, IonPyText, IonPyTimestamp
   from amazon.ion.simpleion import dumps, loads
   
   logger = getLogger(__name__)
   basicConfig(level=INFO)
   IonValue = (IonPyBool, IonPyBytes, IonPyDecimal, IonPyDict, IonPyFloat, IonPyInt, IonPyList, IonPyNull, IonPySymbol,
               IonPyText, IonPyTimestamp)
   
   
   class SampleData:
       """
       Sample domain objects for use throughout this tutorial.
       """
       DRIVERS_LICENSE = [
           {
               'PersonId': '',
               'LicenseNumber': 'LEWISR261LL',
               'LicenseType': 'Learner',
               'ValidFromDate': datetime(2016, 12, 20),
               'ValidToDate': datetime(2020, 11, 15)
           },
           {
               'PersonId': '',
               'LicenseNumber': 'LOGANB486CG',
               'LicenseType': 'Probationary',
               'ValidFromDate': datetime(2016, 4, 6),
               'ValidToDate': datetime(2020, 11, 15)
           },
           {
               'PersonId': '',
               'LicenseNumber': '744 849 301',
               'LicenseType': 'Full',
               'ValidFromDate': datetime(2017, 12, 6),
               'ValidToDate': datetime(2022, 10, 15)
           },
           {
               'PersonId': '',
               'LicenseNumber': 'P626-168-229-765',
               'LicenseType': 'Learner',
               'ValidFromDate': datetime(2017, 8, 16),
               'ValidToDate': datetime(2021, 11, 15)
           },
           {
               'PersonId': '',
               'LicenseNumber': 'S152-780-97-415-0',
               'LicenseType': 'Probationary',
               'ValidFromDate': datetime(2015, 8, 15),
               'ValidToDate': datetime(2021, 8, 21)
           }
       ]
       PERSON = [
           {
               'FirstName': 'Raul',
               'LastName': 'Lewis',
               'Address': '1719 University Street, Seattle, WA, 98109',
               'DOB': datetime(1963, 8, 19),
               'GovId': 'LEWISR261LL',
               'GovIdType': 'Driver License'
           },
           {
               'FirstName': 'Brent',
               'LastName': 'Logan',
               'DOB': datetime(1967, 7, 3),
               'Address': '43 Stockert Hollow Road, Everett, WA, 98203',
               'GovId': 'LOGANB486CG',
               'GovIdType': 'Driver License'
           },
           {
               'FirstName': 'Alexis',
               'LastName': 'Pena',
               'DOB': datetime(1974, 2, 10),
               'Address': '4058 Melrose Street, Spokane Valley, WA, 99206',
               'GovId': '744 849 301',
               'GovIdType': 'SSN'
           },
           {
               'FirstName': 'Melvin',
               'LastName': 'Parker',
               'DOB': datetime(1976, 5, 22),
               'Address': '4362 Ryder Avenue, Seattle, WA, 98101',
               'GovId': 'P626-168-229-765',
               'GovIdType': 'Passport'
           },
           {
               'FirstName': 'Salvatore',
               'LastName': 'Spencer',
               'DOB': datetime(1997, 11, 15),
               'Address': '4450 Honeysuckle Lane, Seattle, WA, 98101',
               'GovId': 'S152-780-97-415-0',
               'GovIdType': 'Passport'
           }
       ]
       VEHICLE = [
           {
               'VIN': '1N4AL11D75C109151',
               'Type': 'Sedan',
               'Year': 2011,
               'Make': 'Audi',
               'Model': 'A5',
               'Color': 'Silver'
           },
           {
               'VIN': 'KM8SRDHF6EU074761',
               'Type': 'Sedan',
               'Year': 2015,
               'Make': 'Tesla',
               'Model': 'Model S',
               'Color': 'Blue'
           },
           {
               'VIN': '3HGGK5G53FM761765',
               'Type': 'Motorcycle',
               'Year': 2011,
               'Make': 'Ducati',
               'Model': 'Monster 1200',
               'Color': 'Yellow'
           },
           {
               'VIN': '1HVBBAANXWH544237',
               'Type': 'Semi',
               'Year': 2009,
               'Make': 'Ford',
               'Model': 'F 150',
               'Color': 'Black'
           },
           {
               'VIN': '1C4RJFAG0FC625797',
               'Type': 'Sedan',
               'Year': 2019,
               'Make': 'Mercedes',
               'Model': 'CLK 350',
               'Color': 'White'
           }
       ]
       VEHICLE_REGISTRATION = [
           {
               'VIN': '1N4AL11D75C109151',
               'LicensePlateNumber': 'LEWISR261LL',
               'State': 'WA',
               'City': 'Seattle',
               'ValidFromDate': datetime(2017, 8, 21),
               'ValidToDate': datetime(2020, 5, 11),
               'PendingPenaltyTicketAmount': Decimal('90.25'),
               'Owners': {
                   'PrimaryOwner': {'PersonId': ''},
                   'SecondaryOwners': []
               }
           },
           {
               'VIN': 'KM8SRDHF6EU074761',
               'LicensePlateNumber': 'CA762X',
               'State': 'WA',
               'City': 'Kent',
               'PendingPenaltyTicketAmount': Decimal('130.75'),
               'ValidFromDate': datetime(2017, 9, 14),
               'ValidToDate': datetime(2020, 6, 25),
               'Owners': {
                   'PrimaryOwner': {'PersonId': ''},
                   'SecondaryOwners': []
               }
           },
           {
               'VIN': '3HGGK5G53FM761765',
               'LicensePlateNumber': 'CD820Z',
               'State': 'WA',
               'City': 'Everett',
               'PendingPenaltyTicketAmount': Decimal('442.30'),
               'ValidFromDate': datetime(2011, 3, 17),
               'ValidToDate': datetime(2021, 3, 24),
               'Owners': {
                   'PrimaryOwner': {'PersonId': ''},
                   'SecondaryOwners': []
               }
           },
           {
               'VIN': '1HVBBAANXWH544237',
               'LicensePlateNumber': 'LS477D',
               'State': 'WA',
               'City': 'Tacoma',
               'PendingPenaltyTicketAmount': Decimal('42.20'),
               'ValidFromDate': datetime(2011, 10, 26),
               'ValidToDate': datetime(2023, 9, 25),
               'Owners': {
                   'PrimaryOwner': {'PersonId': ''},
                   'SecondaryOwners': []
               }
           },
           {
               'VIN': '1C4RJFAG0FC625797',
               'LicensePlateNumber': 'TH393F',
               'State': 'WA',
               'City': 'Olympia',
               'PendingPenaltyTicketAmount': Decimal('30.45'),
               'ValidFromDate': datetime(2013, 9, 2),
               'ValidToDate': datetime(2024, 3, 19),
               'Owners': {
                   'PrimaryOwner': {'PersonId': ''},
                   'SecondaryOwners': []
               }
           }
       ]
   
   
   def convert_object_to_ion(py_object):
       """
       Convert a Python object into an Ion object.
   
       :type py_object: object
       :param py_object: The object to convert.
   
       :rtype: :py:class:`amazon.ion.simple_types.IonPyValue`
       :return: The converted Ion object.
       """
       ion_object = loads(dumps(py_object))
       return ion_object
   
   
   def to_ion_struct(key, value):
       """
       Convert the given key and value into an Ion struct.
   
       :type key: str
       :param key: The key which serves as an unique identifier.
   
       :type value: str
       :param value: The value associated with a given key.
   
       :rtype: :py:class:`amazon.ion.simple_types.IonPyDict`
       :return: The Ion dictionary object.
       """
       ion_struct = dict()
       ion_struct[key] = value
       return loads(str(ion_struct))
   
   
   def get_document_ids(transaction_executor, table_name, field, value):
       """
       Gets the document IDs from the given table.
   
       :type transaction_executor: :py:class:`pyqldb.execution.executor.Executor`
       :param transaction_executor: An Executor object allowing for execution of statements within a transaction.
   
       :type table_name: str
       :param table_name: The table name to query.
   
       :type field: str
       :param field: A field to query.
   
       :type value: str
       :param value: The key of the given field.
   
       :rtype: list
       :return: A list of document IDs.
       """
       query = "SELECT id FROM {} AS t BY id WHERE t.{} = ?".format(table_name, field)
       cursor = transaction_executor.execute_statement(query, convert_object_to_ion(value))
       return list(map(lambda table: table.get('id'), cursor))
   
   
   def get_document_ids_from_dml_results(result):
       """
       Return a list of modified document IDs as strings from DML results.
   
       :type result: :py:class:`pyqldb.cursor.buffered_cursor.BufferedCursor`
       :param: result: The result set from DML operation.
   
       :rtype: list
       :return: List of document IDs.
       """
       ret_val = list(map(lambda x: x.get('documentId'), result))
       return ret_val
   
   
   def print_result(cursor):
       """
       Pretty print the result set. Returns the number of documents in the result set.
   
       :type cursor: :py:class:`pyqldb.cursor.stream_cursor.StreamCursor`/
                     :py:class:`pyqldb.cursor.buffered_cursor.BufferedCursor`
       :param cursor: An instance of the StreamCursor or BufferedCursor class.
   
       :rtype: int
       :return: Number of documents in the result set.
       """
       result_counter = 0
       for row in cursor:
           # Each row would be in Ion format.
           print_ion(row)
           result_counter += 1
       return result_counter
   
   
   def print_ion(ion_value):
       """
       Pretty print an Ion Value.
   
       :type ion_value: :py:class:`amazon.ion.simple_types.IonPySymbol`
       :param ion_value: Any Ion Value to be pretty printed.
       """
       logger.info(dumps(ion_value, binary=False, indent='  ', omit_version_marker=True))
   ```
**Nota**  
La `get_document_ids` funzione esegue una query che restituisce un documento IDs assegnato dal sistema da una tabella. Per ulteriori informazioni, consulta [Utilizzo della clausola BY per interrogare l'ID del documento](working.metadata.by-clause.md).

1. Utilizzate il seguente programma (`insert_document.py`) per inserire i dati di esempio nelle tabelle.

------
#### [ 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 logging import basicConfig, getLogger, INFO
   
   from pyqldbsamples.constants import Constants
   from pyqldbsamples.model.sample_data import convert_object_to_ion, SampleData, get_document_ids_from_dml_results
   from pyqldbsamples.connect_to_ledger import create_qldb_driver
   
   logger = getLogger(__name__)
   basicConfig(level=INFO)
   
   
   def update_person_id(document_ids):
       """
       Update the PersonId value for DriversLicense records and the PrimaryOwner value for VehicleRegistration records.
   
       :type document_ids: list
       :param document_ids: List of document IDs.
   
       :rtype: list
       :return: Lists of updated DriversLicense records and updated VehicleRegistration records.
       """
       new_drivers_licenses = SampleData.DRIVERS_LICENSE.copy()
       new_vehicle_registrations = SampleData.VEHICLE_REGISTRATION.copy()
       for i in range(len(SampleData.PERSON)):
           drivers_license = new_drivers_licenses[i]
           registration = new_vehicle_registrations[i]
           drivers_license.update({'PersonId': str(document_ids[i])})
           registration['Owners']['PrimaryOwner'].update({'PersonId': str(document_ids[i])})
       return new_drivers_licenses, new_vehicle_registrations
   
   
   def insert_documents(driver, table_name, documents):
       """
       Insert the given list of documents into a table in a single transaction.
   
       :type driver: :py:class:`pyqldb.driver.qldb_driver.QldbDriver`
       :param driver: An instance of the QldbDriver class.
   
       :type table_name: str
       :param table_name: Name of the table to insert documents into.
   
       :type documents: list
       :param documents: List of documents to insert.
   
       :rtype: list
       :return: List of documents IDs for the newly inserted documents.
       """
       logger.info('Inserting some documents in the {} table...'.format(table_name))
       statement = 'INSERT INTO {} ?'.format(table_name)
       cursor = driver.execute_lambda(lambda executor: executor.execute_statement(statement,
                                                                                  convert_object_to_ion(documents)))
       list_of_document_ids = get_document_ids_from_dml_results(cursor)
   
       return list_of_document_ids
   
   
   def update_and_insert_documents(driver):
       """
       Handle the insertion of documents and updating PersonIds.
   
       :type driver: :py:class:`pyqldb.driver.qldb_driver.QldbDriver`
       :param driver: An instance of the QldbDriver class.
       """
       list_ids = insert_documents(driver, Constants.PERSON_TABLE_NAME, SampleData.PERSON)
   
       logger.info("Updating PersonIds for 'DriversLicense' and PrimaryOwner for 'VehicleRegistration'...")
       new_licenses, new_registrations = update_person_id(list_ids)
   
       insert_documents(driver, Constants.VEHICLE_TABLE_NAME, SampleData.VEHICLE)
       insert_documents(driver, Constants.VEHICLE_REGISTRATION_TABLE_NAME, new_registrations)
       insert_documents(driver, Constants.DRIVERS_LICENSE_TABLE_NAME, new_licenses)
   
   
   def main(ledger_name=Constants.LEDGER_NAME):
       """
       Insert documents into a table in a QLDB ledger.
       """
       try:
           with create_qldb_driver(ledger_name) as driver:
               # An INSERT statement creates the initial revision of a document with a version number of zero.
               # QLDB also assigns a unique document identifier in GUID format as part of the metadata.
               update_and_insert_documents(driver)
               logger.info('Documents inserted successfully!')
       except Exception as e:
           logger.exception('Error inserting or updating documents.')
           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 logging import basicConfig, getLogger, INFO
   
   from pyqldbsamples.constants import Constants
   from pyqldbsamples.model.sample_data import convert_object_to_ion, SampleData, get_document_ids_from_dml_results
   from pyqldbsamples.connect_to_ledger import create_qldb_session
   
   logger = getLogger(__name__)
   basicConfig(level=INFO)
   
   
   def update_person_id(document_ids):
       """
       Update the PersonId value for DriversLicense records and the PrimaryOwner value for VehicleRegistration records.
   
       :type document_ids: list
       :param document_ids: List of document IDs.
   
       :rtype: list
       :return: Lists of updated DriversLicense records and updated VehicleRegistration records.
       """
       new_drivers_licenses = SampleData.DRIVERS_LICENSE.copy()
       new_vehicle_registrations = SampleData.VEHICLE_REGISTRATION.copy()
       for i in range(len(SampleData.PERSON)):
           drivers_license = new_drivers_licenses[i]
           registration = new_vehicle_registrations[i]
           drivers_license.update({'PersonId': str(document_ids[i])})
           registration['Owners']['PrimaryOwner'].update({'PersonId': str(document_ids[i])})
       return new_drivers_licenses, new_vehicle_registrations
   
   
   def insert_documents(transaction_executor, table_name, documents):
       """
       Insert the given list of documents into a table in a single transaction.
   
       :type transaction_executor: :py:class:`pyqldb.execution.executor.Executor`
       :param transaction_executor: An Executor object allowing for execution of statements within a transaction.
   
       :type table_name: str
       :param table_name: Name of the table to insert documents into.
   
       :type documents: list
       :param documents: List of documents to insert.
   
       :rtype: list
       :return: List of documents IDs for the newly inserted documents.
       """
       logger.info('Inserting some documents in the {} table...'.format(table_name))
       statement = 'INSERT INTO {} ?'.format(table_name)
       cursor = transaction_executor.execute_statement(statement, convert_object_to_ion(documents))
       list_of_document_ids = get_document_ids_from_dml_results(cursor)
   
       return list_of_document_ids
   
   
   def update_and_insert_documents(transaction_executor):
       """
       Handle the insertion of documents and updating PersonIds all in a single transaction.
   
       :type transaction_executor: :py:class:`pyqldb.execution.executor.Executor`
       :param transaction_executor: An Executor object allowing for execution of statements within a transaction.
       """
       list_ids = insert_documents(transaction_executor, Constants.PERSON_TABLE_NAME, SampleData.PERSON)
   
       logger.info("Updating PersonIds for 'DriversLicense' and PrimaryOwner for 'VehicleRegistration'...")
       new_licenses, new_registrations = update_person_id(list_ids)
   
       insert_documents(transaction_executor, Constants.VEHICLE_TABLE_NAME, SampleData.VEHICLE)
       insert_documents(transaction_executor, Constants.VEHICLE_REGISTRATION_TABLE_NAME, new_registrations)
       insert_documents(transaction_executor, Constants.DRIVERS_LICENSE_TABLE_NAME, new_licenses)
   
   
   if __name__ == '__main__':
       """
       Insert documents into a table in a QLDB ledger.
       """
       try:
           with create_qldb_session() as session:
               # An INSERT statement creates the initial revision of a document with a version number of zero.
               # QLDB also assigns a unique document identifier in GUID format as part of the metadata.
               session.execute_lambda(lambda executor: update_and_insert_documents(executor),
                                      lambda retry_attempt: logger.info('Retrying due to OCC conflict...'))
               logger.info('Documents inserted successfully!')
       except Exception:
           logger.exception('Error inserting or updating documents.')
   ```

------
**Nota**  
Questo programma dimostra come chiamare la `execute_statement` funzione con valori parametrizzati. È possibile passare parametri di dati oltre all'istruzione PartiQL che si desidera eseguire. Utilizzate un punto interrogativo (`?`) come segnaposto variabile nella stringa dell'istruzione.
Se un'`INSERT`istruzione ha esito positivo, restituisce il valore `id` di ogni documento inserito.

1. Per eseguire il programma, immetti il comando seguente:

   ```
   python insert_document.py
   ```

Successivamente, è possibile utilizzare `SELECT` le istruzioni per leggere i dati dalle tabelle del `vehicle-registration` libro mastro. Passa a [Passaggio 4: interrogare le tabelle in un libro mastro](getting-started.python.step-4.md).

# Passaggio 4: interrogare le tabelle in un libro mastro
<a name="getting-started.python.step-4"></a>

**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 creato tabelle in un registro Amazon QLDB e averle caricate con i dati, puoi eseguire query per rivedere i dati di immatricolazione dei veicoli che hai appena inserito. QLDB [utilizza](ql-reference.md) PartiQL come linguaggio di interrogazione [e Amazon](ion.md) Ion come modello di dati orientato ai documenti.

PartiQL è un linguaggio di query open source compatibile con SQL che è stato esteso per funzionare con Ion. Con PartiQL, puoi inserire, interrogare e gestire i tuoi dati con operatori SQL familiari. Amazon Ion è un superset di JSON. Ion è un formato di dati open source basato su documenti che offre la flessibilità di archiviazione ed elaborazione di dati strutturati, semistrutturati e annidati.

In questo passaggio, si utilizzano `SELECT` le istruzioni per leggere i dati dalle tabelle del registro. `vehicle-registration`

**avvertimento**  
Quando si esegue una query in QLDB senza una ricerca indicizzata, viene richiamata una scansione completa della tabella. PartiQL supporta tali query perché è compatibile con SQL. Tuttavia, *non* eseguire scansioni di tabelle per casi d'uso di produzione in QLDB. Le scansioni delle tabelle possono causare problemi di prestazioni su tabelle di grandi dimensioni, inclusi conflitti di concorrenza e timeout delle transazioni.  
Per evitare le scansioni delle tabelle, è necessario eseguire istruzioni con una clausola di `WHERE` predicato utilizzando un operatore di *uguaglianza* su un campo indicizzato o un ID di documento; ad esempio, o. `WHERE indexedField = 123` `WHERE indexedField IN (456, 789)` Per ulteriori informazioni, consulta [Ottimizzazione delle prestazioni delle query](working.optimize.md).

**Per interrogare le tabelle**

1. Usa il seguente programma (`find_vehicles.py`) per interrogare tutti i veicoli registrati con una persona nel tuo registro.

------
#### [ 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 logging import basicConfig, getLogger, INFO
   
   from pyqldbsamples.model.sample_data import get_document_ids, print_result, SampleData
   from pyqldbsamples.constants import Constants
   from pyqldbsamples.connect_to_ledger import create_qldb_driver
   
   logger = getLogger(__name__)
   basicConfig(level=INFO)
   
   
   def find_vehicles_for_owner(driver, gov_id):
       """
       Find vehicles registered under a driver using their government ID.
   
       :type driver: :py:class:`pyqldb.driver.qldb_driver.QldbDriver`
       :param driver: An instance of the QldbDriver class.
   
       :type gov_id: str
       :param gov_id: The owner's government ID.
       """
       document_ids = driver.execute_lambda(lambda executor: get_document_ids(executor, Constants.PERSON_TABLE_NAME,
                                                                              'GovId', gov_id))
   
       query = "SELECT Vehicle FROM Vehicle INNER JOIN VehicleRegistration AS r " \
               "ON Vehicle.VIN = r.VIN WHERE r.Owners.PrimaryOwner.PersonId = ?"
   
       for ids in document_ids:
           cursor = driver.execute_lambda(lambda executor: executor.execute_statement(query, ids))
           logger.info('List of Vehicles for owner with GovId: {}...'.format(gov_id))
           print_result(cursor)
   
   
   def main(ledger_name=Constants.LEDGER_NAME):
       """
       Find all vehicles registered under a person.
       """
       try:
           with create_qldb_driver(ledger_name) as driver:
               # Find all vehicles registered under a person.
               gov_id = SampleData.PERSON[0]['GovId']
               find_vehicles_for_owner(driver, gov_id)
       except Exception as e:
           logger.exception('Error getting vehicles for owner.')
           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 logging import basicConfig, getLogger, INFO
   
   from pyqldbsamples.model.sample_data import get_document_ids, print_result, SampleData
   from pyqldbsamples.constants import Constants
   from pyqldbsamples.connect_to_ledger import create_qldb_session
   
   logger = getLogger(__name__)
   basicConfig(level=INFO)
   
   
   def find_vehicles_for_owner(transaction_executor, gov_id):
       """
       Find vehicles registered under a driver using their government ID.
   
       :type transaction_executor: :py:class:`pyqldb.execution.executor.Executor`
       :param transaction_executor: An Executor object allowing for execution of statements within a transaction.
   
       :type gov_id: str
       :param gov_id: The owner's government ID.
       """
       document_ids = get_document_ids(transaction_executor, Constants.PERSON_TABLE_NAME, 'GovId', gov_id)
   
       query = "SELECT Vehicle FROM Vehicle INNER JOIN VehicleRegistration AS r " \
               "ON Vehicle.VIN = r.VIN WHERE r.Owners.PrimaryOwner.PersonId = ?"
   
       for ids in document_ids:
           cursor = transaction_executor.execute_statement(query, ids)
           logger.info('List of Vehicles for owner with GovId: {}...'.format(gov_id))
           print_result(cursor)
   
   
   if __name__ == '__main__':
       """
       Find all vehicles registered under a person.
       """
       try:
           with create_qldb_session() as session:
               # Find all vehicles registered under a person.
               gov_id = SampleData.PERSON[0]['GovId']
               session.execute_lambda(lambda executor: find_vehicles_for_owner(executor, gov_id),
                                      lambda retry_attempt: logger.info('Retrying due to OCC conflict...'))
       except Exception:
           logger.exception('Error getting vehicles for owner.')
   ```

------
**Nota**  
Innanzitutto, questo programma interroga la `Person` tabella del documento per ottenere il relativo `GovId LEWISR261LL` campo di `id` metadati.  
Quindi, utilizza questo documento `id` come chiave esterna per interrogare la `VehicleRegistration` tabella. `PrimaryOwner.PersonId` Inoltre si unisce `VehicleRegistration` alla `Vehicle` tabella sul `VIN` campo.

1. Per eseguire il programma, immetti il comando seguente:

   ```
   python find_vehicles.py
   ```

Per ulteriori informazioni sulla modifica dei documenti nelle tabelle del `vehicle-registration` libro mastro, consulta. [Fase 5: Modificare i documenti in un libro mastro](getting-started.python.step-5.md)

# Fase 5: Modificare i documenti in un libro mastro
<a name="getting-started.python.step-5"></a>

**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/).

Ora che hai dei dati su cui lavorare, puoi iniziare a modificare i documenti nel `vehicle-registration` registro di Amazon QLDB. In questa fase, i seguenti esempi di codice mostrano come eseguire istruzioni DML (Data Manipulation Language). Queste istruzioni aggiornano il proprietario principale di un veicolo e aggiungono un proprietario secondario a un altro veicolo.

**Per modificare i documenti**

1. Utilizzate il seguente programma (`transfer_vehicle_ownership.py`) per aggiornare il proprietario principale del veicolo inserendo il `1N4AL11D75C109151` VIN nel registro.

------
#### [ 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 logging import basicConfig, getLogger, INFO
   
   from pyqldbsamples.add_secondary_owner import get_document_ids, print_result, SampleData
   from pyqldbsamples.constants import Constants
   from pyqldbsamples.model.sample_data import convert_object_to_ion
   from pyqldbsamples.connect_to_ledger import create_qldb_driver
   
   logger = getLogger(__name__)
   basicConfig(level=INFO)
   
   
   def find_person_from_document_id(transaction_executor, document_id):
       """
       Query a driver's information using the given ID.
   
       :type transaction_executor: :py:class:`pyqldb.execution.executor.Executor`
       :param transaction_executor: An Executor object allowing for execution of statements within a transaction.
   
       :type document_id: :py:class:`amazon.ion.simple_types.IonPyText`
       :param document_id: The document ID required to query for the person.
   
       :rtype: :py:class:`amazon.ion.simple_types.IonPyDict`
       :return: The resulting document from the query.
       """
       query = 'SELECT p.* FROM Person AS p BY pid WHERE pid = ?'
       cursor = transaction_executor.execute_statement(query, document_id)
       return next(cursor)
   
   
   def find_primary_owner_for_vehicle(driver, vin):
       """
       Find the primary owner of a vehicle given its VIN.
   
       :type driver: :py:class:`pyqldb.driver.qldb_driver.QldbDriver`
       :param driver: An instance of the QldbDriver class.
   
       :type vin: str
       :param vin: The VIN to find primary owner for.
   
       :rtype: :py:class:`amazon.ion.simple_types.IonPyDict`
       :return: The resulting document from the query.
       """
       logger.info('Finding primary owner for vehicle with VIN: {}.'.format(vin))
       query = "SELECT Owners.PrimaryOwner.PersonId FROM VehicleRegistration AS v WHERE v.VIN = ?"
       cursor = driver.execute_lambda(lambda executor: executor.execute_statement(query, convert_object_to_ion(vin)))
       try:
           return driver.execute_lambda(lambda executor: find_person_from_document_id(executor,
                                                                                      next(cursor).get('PersonId')))
       except StopIteration:
           logger.error('No primary owner registered for this vehicle.')
           return None
   
   
   def update_vehicle_registration(driver, vin, document_id):
       """
       Update the primary owner for a vehicle using the given VIN.
   
       :type driver: :py:class:`pyqldb.driver.qldb_driver.QldbDriver`
       :param driver: An instance of the QldbDriver class.
   
       :type vin: str
       :param vin: The VIN for the vehicle to operate on.
   
       :type document_id: :py:class:`amazon.ion.simple_types.IonPyText`
       :param document_id: New PersonId for the primary owner.
   
       :raises RuntimeError: If no vehicle registration was found using the given document ID and VIN.
       """
       logger.info('Updating the primary owner for vehicle with Vin: {}...'.format(vin))
       statement = "UPDATE VehicleRegistration AS r SET r.Owners.PrimaryOwner.PersonId = ? WHERE r.VIN = ?"
       cursor = driver.execute_lambda(lambda executor: executor.execute_statement(statement, document_id,
                                                                                  convert_object_to_ion(vin)))
       try:
           print_result(cursor)
           logger.info('Successfully transferred vehicle with VIN: {} to new owner.'.format(vin))
       except StopIteration:
           raise RuntimeError('Unable to transfer vehicle, could not find registration.')
   
   
   def validate_and_update_registration(driver, vin, current_owner, new_owner):
       """
       Validate the current owner of the given vehicle and transfer its ownership to a new owner.
   
       :type driver: :py:class:`pyqldb.driver.qldb_driver.QldbDriver`
       :param driver: An instance of the QldbDriver class.
   
       :type vin: str
       :param vin: The VIN of the vehicle to transfer ownership of.
   
       :type current_owner: str
       :param current_owner: The GovId of the current owner of the vehicle.
   
       :type new_owner: str
       :param new_owner: The GovId of the new owner of the vehicle.
   
       :raises RuntimeError: If unable to verify primary owner.
       """
       primary_owner = find_primary_owner_for_vehicle(driver, vin)
       if primary_owner is None or primary_owner['GovId'] != current_owner:
           raise RuntimeError('Incorrect primary owner identified for vehicle, unable to transfer.')
   
       document_ids = driver.execute_lambda(lambda executor: get_document_ids(executor, Constants.PERSON_TABLE_NAME,
                                                                              'GovId', new_owner))
       update_vehicle_registration(driver, vin, document_ids[0])
   
   
   def main(ledger_name=Constants.LEDGER_NAME):
       """
       Find primary owner for a particular vehicle's VIN.
       Transfer to another primary owner for a particular vehicle's VIN.
       """
       vehicle_vin = SampleData.VEHICLE[0]['VIN']
       previous_owner = SampleData.PERSON[0]['GovId']
       new_owner = SampleData.PERSON[1]['GovId']
   
       try:
           with create_qldb_driver(ledger_name) as driver:
               validate_and_update_registration(driver, vehicle_vin, previous_owner, new_owner)
       except Exception as e:
           logger.exception('Error updating VehicleRegistration.')
           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 logging import basicConfig, getLogger, INFO
   
   from pyqldbsamples.add_secondary_owner import get_document_ids, print_result, SampleData
   from pyqldbsamples.constants import Constants
   from pyqldbsamples.model.sample_data import convert_object_to_ion
   from pyqldbsamples.connect_to_ledger import create_qldb_session
   
   logger = getLogger(__name__)
   basicConfig(level=INFO)
   
   
   def find_person_from_document_id(transaction_executor, document_id):
       """
       Query a driver's information using the given ID.
   
       :type transaction_executor: :py:class:`pyqldb.execution.executor.Executor`
       :param transaction_executor: An Executor object allowing for execution of statements within a transaction.
   
       :type document_id: :py:class:`amazon.ion.simple_types.IonPyText`
       :param document_id: The document ID required to query for the person.
   
       :rtype: :py:class:`amazon.ion.simple_types.IonPyDict`
       :return: The resulting document from the query.
       """
       query = 'SELECT p.* FROM Person AS p BY pid WHERE pid = ?'
       cursor = transaction_executor.execute_statement(query, document_id)
       return next(cursor)
   
   
   def find_primary_owner_for_vehicle(transaction_executor, vin):
       """
       Find the primary owner of a vehicle given its 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: The VIN to find primary owner for.
   
       :rtype: :py:class:`amazon.ion.simple_types.IonPyDict`
       :return: The resulting document from the query.
       """
       logger.info('Finding primary owner for vehicle with VIN: {}.'.format(vin))
       query = "SELECT Owners.PrimaryOwner.PersonId FROM VehicleRegistration AS v WHERE v.VIN = ?"
       cursor = transaction_executor.execute_statement(query, convert_object_to_ion(vin))
       try:
           return find_person_from_document_id(transaction_executor, next(cursor).get('PersonId'))
       except StopIteration:
           logger.error('No primary owner registered for this vehicle.')
           return None
   
   
   def update_vehicle_registration(transaction_executor, vin, document_id):
       """
       Update the primary owner for a vehicle using the given 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: The VIN for the vehicle to operate on.
   
       :type document_id: :py:class:`amazon.ion.simple_types.IonPyText`
       :param document_id: New PersonId for the primary owner.
   
       :raises RuntimeError: If no vehicle registration was found using the given document ID and VIN.
       """
       logger.info('Updating the primary owner for vehicle with Vin: {}...'.format(vin))
       statement = "UPDATE VehicleRegistration AS r SET r.Owners.PrimaryOwner.PersonId = ? WHERE r.VIN = ?"
       cursor = transaction_executor.execute_statement(statement, document_id, convert_object_to_ion(vin))
       try:
           print_result(cursor)
           logger.info('Successfully transferred vehicle with VIN: {} to new owner.'.format(vin))
       except StopIteration:
           raise RuntimeError('Unable to transfer vehicle, could not find registration.')
   
   
   def validate_and_update_registration(transaction_executor, vin, current_owner, new_owner):
       """
       Validate the current owner of the given vehicle and transfer its ownership to a new owner in a single transaction.
   
       :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: The VIN of the vehicle to transfer ownership of.
   
       :type current_owner: str
       :param current_owner: The GovId of the current owner of the vehicle.
   
       :type new_owner: str
       :param new_owner: The GovId of the new owner of the vehicle.
   
       :raises RuntimeError: If unable to verify primary owner.
       """
       primary_owner = find_primary_owner_for_vehicle(transaction_executor, vin)
       if primary_owner is None or primary_owner['GovId'] != current_owner:
           raise RuntimeError('Incorrect primary owner identified for vehicle, unable to transfer.')
   
       document_id = next(get_document_ids(transaction_executor, Constants.PERSON_TABLE_NAME, 'GovId', new_owner))
   
       update_vehicle_registration(transaction_executor, vin, document_id)
   
   
   if __name__ == '__main__':
       """
       Find primary owner for a particular vehicle's VIN.
       Transfer to another primary owner for a particular vehicle's VIN.
       """
       vehicle_vin = SampleData.VEHICLE[0]['VIN']
       previous_owner = SampleData.PERSON[0]['GovId']
       new_owner = SampleData.PERSON[1]['GovId']
   
       try:
           with create_qldb_session() as session:
               session.execute_lambda(lambda executor: validate_and_update_registration(executor, vehicle_vin,
                                                                                        previous_owner, new_owner),
                                      retry_indicator=lambda retry_attempt: logger.info('Retrying due to OCC conflict...'))
       except Exception:
           logger.exception('Error updating VehicleRegistration.')
   ```

------

1. Per eseguire il programma, immetti il comando seguente:

   ```
   python transfer_vehicle_ownership.py
   ```

1. Utilizza il seguente programma (`add_secondary_owner.py`) per aggiungere un proprietario secondario al veicolo con VIN `KM8SRDHF6EU074761` nel registro.

------
#### [ 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 logging import basicConfig, getLogger, INFO
   
   from pyqldbsamples.model.sample_data import to_ion_struct, get_document_ids, print_result, SampleData, \
       convert_object_to_ion
   from pyqldbsamples.constants import Constants
   from pyqldbsamples.connect_to_ledger import create_qldb_driver
   
   logger = getLogger(__name__)
   basicConfig(level=INFO)
   
   
   def get_document_id_by_gov_id(driver, government_id):
       """
       Find a driver's person ID using the given government ID.
   
       :type driver: :py:class:`pyqldb.driver.qldb_driver.QldbDriver`
       :param driver: An instance of the QldbDriver class.
   
       :type government_id: str
       :param government_id: A driver's government ID.
   
       :rtype: list
       :return: A list of document IDs.
       """
       logger.info("Finding secondary owner's person ID using given government ID: {}.".format(government_id))
       return driver.execute_lambda(lambda executor: get_document_ids(executor, Constants.PERSON_TABLE_NAME, 'GovId',
                                                                      government_id))
   
   
   def is_secondary_owner_for_vehicle(driver, vin, secondary_owner_id):
       """
       Check whether a secondary owner has already been registered for the given VIN.
   
       :type driver: :py:class:`pyqldb.driver.qldb_driver.QldbDriver`
       :param driver: An instance of the QldbDriver class.
   
       :type vin: str
       :param vin: VIN of the vehicle to query.
   
       :type secondary_owner_id: str
       :param secondary_owner_id: The secondary owner's person ID.
   
       :rtype: bool
       :return: If the driver has already been registered.
       """
       logger.info('Finding secondary owners for vehicle with VIN: {}...'.format(vin))
       query = 'SELECT Owners.SecondaryOwners FROM VehicleRegistration AS v WHERE v.VIN = ?'
       rows = driver.execute_lambda(lambda executor: executor.execute_statement(query, convert_object_to_ion(vin)))
   
       for row in rows:
           secondary_owners = row.get('SecondaryOwners')
           person_ids = map(lambda owner: owner.get('PersonId').text, secondary_owners)
           if secondary_owner_id in person_ids:
               return True
       return False
   
   
   def add_secondary_owner_for_vin(driver, vin, parameter):
       """
       Add a secondary owner into `VehicleRegistration` table for a particular VIN.
   
       :type driver: :py:class:`pyqldb.driver.qldb_driver.QldbDriver`
       :param driver: An instance of the QldbDriver class.
   
       :type vin: str
       :param vin: VIN of the vehicle to add a secondary owner for.
   
       :type parameter: :py:class:`amazon.ion.simple_types.IonPyValue`
       :param parameter: The Ion value or Python native type that is convertible to Ion for filling in parameters of the
                         statement.
       """
       logger.info('Inserting secondary owner for vehicle with VIN: {}...'.format(vin))
       statement = "FROM VehicleRegistration AS v WHERE v.VIN = ? INSERT INTO v.Owners.SecondaryOwners VALUE ?"
   
       cursor = driver.execute_lambda(lambda executor: executor.execute_statement(statement, convert_object_to_ion(vin),
                                                                                  parameter))
       logger.info('VehicleRegistration Document IDs which had secondary owners added: ')
       print_result(cursor)
   
   
   def register_secondary_owner(driver, vin, gov_id):
       """
       Register a secondary owner for a vehicle if they are not already registered.
   
       :type driver: :py:class:`pyqldb.driver.qldb_driver.QldbDriver`
       :param driver: An instance of the QldbDriver class.
   
       :type vin: str
       :param vin: VIN of the vehicle to register a secondary owner for.
   
       :type gov_id: str
       :param gov_id: The government ID of the owner.
       """
       logger.info('Finding the secondary owners for vehicle with VIN: {}.'.format(vin))
   
       document_ids = get_document_id_by_gov_id(driver, gov_id)
   
       for document_id in document_ids:
           if is_secondary_owner_for_vehicle(driver, vin, document_id):
               logger.info('Person with ID {} has already been added as a secondary owner of this vehicle.'.format(gov_id))
           else:
               add_secondary_owner_for_vin(driver, vin, to_ion_struct('PersonId', document_id))
   
   
   def main(ledger_name=Constants.LEDGER_NAME):
       """
       Finds and adds secondary owners for a vehicle.
       """
       vin = SampleData.VEHICLE[1]['VIN']
       gov_id = SampleData.PERSON[0]['GovId']
       try:
           with create_qldb_driver(ledger_name) as driver:
               register_secondary_owner(driver, vin, gov_id)
               logger.info('Secondary owners successfully updated.')
       except Exception as e:
           logger.exception('Error adding secondary owner.')
           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 logging import basicConfig, getLogger, INFO
   
   from pyqldbsamples.model.sample_data import to_ion_struct, get_document_ids, print_result, SampleData, \
       convert_object_to_ion
   from pyqldbsamples.constants import Constants
   from pyqldbsamples.connect_to_ledger import create_qldb_session
   
   logger = getLogger(__name__)
   basicConfig(level=INFO)
   
   
   def get_document_id_by_gov_id(transaction_executor, government_id):
       """
       Find a driver's person ID using the given government ID.
       :type transaction_executor: :py:class:`pyqldb.execution.executor.Executor`
       :param transaction_executor: An Executor object allowing for execution of statements within a transaction.
       :type government_id: str
       :param government_id: A driver's government ID.
       :rtype: list
       :return: A list of document IDs.
       """
       logger.info("Finding secondary owner's person ID using given government ID: {}.".format(government_id))
       return get_document_ids(transaction_executor, Constants.PERSON_TABLE_NAME, 'GovId', government_id)
   
   
   def is_secondary_owner_for_vehicle(transaction_executor, vin, secondary_owner_id):
       """
       Check whether a secondary owner has already been registered for the given 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 of the vehicle to query.
       :type secondary_owner_id: str
       :param secondary_owner_id: The secondary owner's person ID.
       :rtype: bool
       :return: If the driver has already been registered.
       """
       logger.info('Finding secondary owners for vehicle with VIN: {}...'.format(vin))
       query = 'SELECT Owners.SecondaryOwners FROM VehicleRegistration AS v WHERE v.VIN = ?'
       rows = transaction_executor.execute_statement(query, convert_object_to_ion(vin))
   
       for row in rows:
           secondary_owners = row.get('SecondaryOwners')
           person_ids = map(lambda owner: owner.get('PersonId').text, secondary_owners)
           if secondary_owner_id in person_ids:
               return True
       return False
   
   
   def add_secondary_owner_for_vin(transaction_executor, vin, parameter):
       """
       Add a secondary owner into `VehicleRegistration` table for a particular 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 of the vehicle to add a secondary owner for.
       :type parameter: :py:class:`amazon.ion.simple_types.IonPyValue`
       :param parameter: The Ion value or Python native type that is convertible to Ion for filling in parameters of the
                         statement.
       """
       logger.info('Inserting secondary owner for vehicle with VIN: {}...'.format(vin))
       statement = "FROM VehicleRegistration AS v WHERE v.VIN = '{}' INSERT INTO v.Owners.SecondaryOwners VALUE ?"\
           .format(vin)
   
       cursor = transaction_executor.execute_statement(statement, parameter)
       logger.info('VehicleRegistration Document IDs which had secondary owners added: ')
       print_result(cursor)
   
   
   def register_secondary_owner(transaction_executor, vin, gov_id):
       """
       Register a secondary owner for a vehicle if they are not already registered.
       :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 of the vehicle to register a secondary owner for.
       :type gov_id: str
       :param gov_id: The government ID of the owner.
       """
       logger.info('Finding the secondary owners for vehicle with VIN: {}.'.format(vin))
       document_ids = get_document_id_by_gov_id(transaction_executor, gov_id)
   
       for document_id in document_ids:
           if is_secondary_owner_for_vehicle(transaction_executor, vin, document_id):
               logger.info('Person with ID {} has already been added as a secondary owner of this vehicle.'.format(gov_id))
           else:
               add_secondary_owner_for_vin(transaction_executor, vin, to_ion_struct('PersonId', document_id))
   
   
   if __name__ == '__main__':
       """
       Finds and adds secondary owners for a vehicle.
       """
       vin = SampleData.VEHICLE[1]['VIN']
       gov_id = SampleData.PERSON[0]['GovId']
       try:
           with create_qldb_session() as session:
               session.execute_lambda(lambda executor: register_secondary_owner(executor, vin, gov_id),
                                      lambda retry_attempt: logger.info('Retrying due to OCC conflict...'))
               logger.info('Secondary owners successfully updated.')
       except Exception:
           logger.exception('Error adding secondary owner.')
   ```

------

1. Per eseguire il programma, immetti il comando seguente:

   ```
   python add_secondary_owner.py
   ```

Per esaminare queste modifiche nel `vehicle-registration` libro mastro, consulta. [Fase 6: Visualizzare la cronologia delle revisioni di un documento](getting-started.python.step-6.md)

# Fase 6: Visualizzare la cronologia delle revisioni di un documento
<a name="getting-started.python.step-6"></a>

**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)

# Fase 7: Verificare un documento in un libro mastro
<a name="getting-started.python.step-7"></a>

**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/).

Con Amazon QLDB, puoi verificare in modo efficiente l'integrità di un documento nel diario del tuo libro mastro utilizzando l'hashing crittografico con SHA-256. Per ulteriori informazioni su come funzionano la verifica e l'hashing crittografico in QLDB, consulta. [Verifica dei dati in Amazon QLDB](verification.md)

In questo passaggio, verifichi la revisione di un documento nella tabella del `VehicleRegistration` registro. `vehicle-registration` Innanzitutto, richiedi un digest, che viene restituito come file di output e funge da firma dell'intera cronologia delle modifiche del registro. Quindi, richiedi una bozza della revisione relativa a quel digest. Utilizzando questa prova, l'integrità della revisione viene verificata se tutti i controlli di convalida vengono superati.

**Per verificare la revisione di un documento**

1. Esamina i seguenti `.py` file, che rappresentano oggetti QLDB necessari per la verifica e un modulo di utilità con funzioni di supporto per convertire i tipi di risposta QLDB in stringhe.

   1. `block_address.py`

      ```
      # 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.
      
      
      def block_address_to_dictionary(ion_dict):
          """
          Convert a block address from IonPyDict into a dictionary.
          Shape of the dictionary must be: {'IonText': "{strandId: <"strandId">, sequenceNo: <sequenceNo>}"}
      
          :type ion_dict: :py:class:`amazon.ion.simple_types.IonPyDict`/str
          :param ion_dict: The block address value to convert.
      
          :rtype: dict
          :return: The converted dict.
          """
          block_address = {'IonText': {}}
          if not isinstance(ion_dict, str):
              py_dict = '{{strandId: "{}", sequenceNo:{}}}'.format(ion_dict['strandId'], ion_dict['sequenceNo'])
              ion_dict = py_dict
          block_address['IonText'] = ion_dict
          return block_address
      ```

   1. `verifier.py`

      ```
      # 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 array import array
      from base64 import b64encode
      from functools import reduce
      from hashlib import sha256
      from random import randrange
      
      from amazon.ion.simpleion import loads
      
      HASH_LENGTH = 32
      UPPER_BOUND = 8
      
      
      def parse_proof(value_holder):
          """
          Parse the Proof object returned by QLDB into an iterator.
      
          The Proof object returned by QLDB is a dictionary like the following:
          {'IonText': '[{{<hash>}},{{<hash>}}]'}
      
          :type value_holder: dict
          :param value_holder: A structure containing an Ion string value.
      
          :rtype: :py:class:`amazon.ion.simple_types.IonPyList`
          :return: A list of hash values.
          """
          value_holder = value_holder.get('IonText')
          proof_list = loads(value_holder)
          return proof_list
      
      
      def parse_block(value_holder):
          """
          Parse the Block object returned by QLDB and retrieve block hash.
      
          :type value_holder: dict
          :param value_holder: A structure containing an Ion string value.
      
          :rtype: :py:class:`amazon.ion.simple_types.IonPyBytes`
          :return: The block hash.
          """
          value_holder = value_holder.get('IonText')
          block = loads(value_holder)
          block_hash = block.get('blockHash')
          return block_hash
      
      
      def flip_random_bit(original):
          """
          Flip a single random bit in the given hash value.
          This method is used to demonstrate QLDB's verification features.
      
          :type original: bytes
          :param original: The hash value to alter.
      
          :rtype: bytes
          :return: The altered hash with a single random bit changed.
          """
          assert len(original) != 0, 'Invalid bytes.'
      
          altered_position = randrange(len(original))
          bit_shift = randrange(UPPER_BOUND)
          altered_hash = bytearray(original).copy()
      
          altered_hash[altered_position] = altered_hash[altered_position] ^ (1 << bit_shift)
          return bytes(altered_hash)
      
      
      def compare_hash_values(hash1, hash2):
          """
          Compare two hash values by converting them into byte arrays, assuming they are little endian.
      
          :type hash1: bytes
          :param hash1: The hash value to compare.
      
          :type hash2: bytes
          :param hash2: The hash value to compare.
      
          :rtype: int
          :return: Zero if the hash values are equal, otherwise return the difference of the first pair of non-matching bytes.
          """
          assert len(hash1) == HASH_LENGTH
          assert len(hash2) == HASH_LENGTH
      
          hash_array1 = array('b', hash1)
          hash_array2 = array('b', hash2)
      
          for i in range(len(hash_array1) - 1, -1, -1):
              difference = hash_array1[i] - hash_array2[i]
              if difference != 0:
                  return difference
          return 0
      
      
      def join_hash_pairwise(hash1, hash2):
          """
          Take two hash values, sort them, concatenate them, and generate a new hash value from the concatenated values.
      
          :type hash1: bytes
          :param hash1: Hash value to concatenate.
      
          :type hash2: bytes
          :param hash2: Hash value to concatenate.
      
          :rtype: bytes
          :return: The new hash value generated from concatenated hash values.
          """
          if len(hash1) == 0:
              return hash2
          if len(hash2) == 0:
              return hash1
      
          concatenated = hash1 + hash2 if compare_hash_values(hash1, hash2) < 0 else hash2 + hash1
          new_hash_lib = sha256()
          new_hash_lib.update(concatenated)
          new_digest = new_hash_lib.digest()
          return new_digest
      
      
      def calculate_root_hash_from_internal_hashes(internal_hashes, leaf_hash):
          """
          Combine the internal hashes and the leaf hash until only one root hash remains.
      
          :type internal_hashes: map
          :param internal_hashes: An iterable over a list of hash values.
      
          :type leaf_hash: bytes
          :param leaf_hash: The revision hash to pair with the first hash in the Proof hashes list.
      
          :rtype: bytes
          :return: The root hash constructed by combining internal hashes.
          """
          root_hash = reduce(join_hash_pairwise, internal_hashes, leaf_hash)
          return root_hash
      
      
      def build_candidate_digest(proof, leaf_hash):
          """
          Build the candidate digest representing the entire ledger from the Proof hashes.
      
          :type proof: dict
          :param proof: The Proof object.
      
          :type leaf_hash: bytes
          :param leaf_hash: The revision hash to pair with the first hash in the Proof hashes list.
      
          :rtype: bytes
          :return: The calculated root hash.
          """
          parsed_proof = parse_proof(proof)
          root_hash = calculate_root_hash_from_internal_hashes(parsed_proof, leaf_hash)
          return root_hash
      
      
      def verify_document(document_hash, digest, proof):
          """
          Verify document revision against the provided digest.
      
          :type document_hash: bytes
          :param document_hash: The SHA-256 value representing the document revision to be verified.
      
          :type digest: bytes
          :param digest: The SHA-256 hash value representing the ledger digest.
      
          :type proof: dict
          :param proof: The Proof object retrieved from :func:`pyqldbsamples.get_revision.get_revision`.
      
          :rtype: bool
          :return: If the document revision verify against the ledger digest.
          """
          candidate_digest = build_candidate_digest(proof, document_hash)
          return digest == candidate_digest
      
      
      def to_base_64(input):
          """
          Encode input in base64.
      
          :type input: bytes
          :param input: Input to be encoded.
      
          :rtype: string
          :return: Return input that has been encoded in base64.
          """
          encoded_value = b64encode(input)
          return str(encoded_value, 'UTF-8')
      ```

   1. `qldb_string_utils.py`

      ```
      # 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.
      from amazon.ion.simpleion import dumps, loads
      
      
      def value_holder_to_string(value_holder):
          """
          Returns the string representation of a given `value_holder`.
      
          :type value_holder: dict
          :param value_holder: The `value_holder` to convert to string.
      
          :rtype: str
          :return: The string representation of the supplied `value_holder`.
          """
          ret_val = dumps(loads(value_holder), binary=False, indent='  ', omit_version_marker=True)
          val = '{{ IonText: {}}}'.format(ret_val)
          return val
      
      
      def block_response_to_string(block_response):
          """
          Returns the string representation of a given `block_response`.
      
          :type block_response: dict
          :param block_response: The `block_response` to convert to string.
      
          :rtype: str
          :return: The string representation of the supplied `block_response`.
          """
          string = ''
          if block_response.get('Block', {}).get('IonText') is not None:
              string += 'Block: ' + value_holder_to_string(block_response['Block']['IonText']) + ', '
      
          if block_response.get('Proof', {}).get('IonText') is not None:
              string += 'Proof: ' + value_holder_to_string(block_response['Proof']['IonText'])
      
          return '{' + string + '}'
      
      
      def digest_response_to_string(digest_response):
          """
          Returns the string representation of a given `digest_response`.
      
          :type digest_response: dict
          :param digest_response: The `digest_response` to convert to string.
      
          :rtype: str
          :return: The string representation of the supplied `digest_response`.
          """
          string = ''
          if digest_response.get('Digest') is not None:
              string += 'Digest: ' + str(digest_response['Digest']) + ', '
      
          if digest_response.get('DigestTipAddress', {}).get('IonText') is not None:
              string += 'DigestTipAddress: ' + value_holder_to_string(digest_response['DigestTipAddress']['IonText'])
      
          return '{' + string + '}'
      ```

1. Utilizzate due `.py` programmi (`get_digest.py`e`get_revision.py`) per eseguire le seguenti operazioni:
   + Richiedete un nuovo digest dal `vehicle-registration` registro.
   + Richiedi una bozza per ogni revisione del documento con VIN `1N4AL11D75C109151` dalla tabella. `VehicleRegistration`
   + Verifica le revisioni utilizzando il digest restituito e verifica ricalcolando il digest.

   Il `get_digest.py` programma contiene il codice seguente.

   ```
   # 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 logging import basicConfig, getLogger, INFO
   
   from boto3 import client
   
   from pyqldbsamples.constants import Constants
   from pyqldbsamples.qldb.qldb_string_utils import digest_response_to_string
   
   logger = getLogger(__name__)
   basicConfig(level=INFO)
   qldb_client = client('qldb')
   
   
   def get_digest_result(name):
       """
       Get the digest of a ledger's journal.
   
       :type name: str
       :param name: Name of the ledger to operate on.
   
       :rtype: dict
       :return: The digest in a 256-bit hash value and a block address.
       """
       logger.info("Let's get the current digest of the ledger named {}".format(name))
       result = qldb_client.get_digest(Name=name)
       logger.info('Success. LedgerDigest: {}.'.format(digest_response_to_string(result)))
       return result
   
   
   def main(ledger_name=Constants.LEDGER_NAME):
       """
       This is an example for retrieving the digest of a particular ledger.
       """
       try:
           get_digest_result(ledger_name)
       except Exception as e:
           logger.exception('Unable to get a ledger digest!')
           raise e
   
   
   if __name__ == '__main__':
       main()
   ```
**Nota**  
Usa la `get_digest_result` funzione per richiedere un riassunto che copra la *punta* corrente del diario nel tuo libro mastro. Il tip of the journal si riferisce all'ultimo blocco eseguito nel momento in cui QLDB riceve la tua richiesta.

   Il `get_revision.py` programma contiene il seguente codice.

------
#### [ 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 logging import basicConfig, getLogger, INFO
   
   from amazon.ion.simpleion import loads
   from boto3 import client
   
   from pyqldbsamples.constants import Constants
   from pyqldbsamples.get_digest import get_digest_result
   from pyqldbsamples.model.sample_data import SampleData, convert_object_to_ion
   from pyqldbsamples.qldb.block_address import block_address_to_dictionary
   from pyqldbsamples.verifier import verify_document, flip_random_bit, to_base_64
   from pyqldbsamples.connect_to_ledger import create_qldb_driver
   from pyqldbsamples.qldb.qldb_string_utils import value_holder_to_string
   
   logger = getLogger(__name__)
   basicConfig(level=INFO)
   qldb_client = client('qldb')
   
   
   def get_revision(ledger_name, document_id, block_address, digest_tip_address):
       """
       Get the revision data object for a specified document ID and block address.
       Also returns a proof of the specified revision for verification.
   
       :type ledger_name: str
       :param ledger_name: Name of the ledger containing the document to query.
   
       :type document_id: str
       :param document_id: Unique ID for the document to be verified, contained in the committed view of the document.
   
       :type block_address: dict
       :param block_address: The location of the block to request.
   
       :type digest_tip_address: dict
       :param digest_tip_address: The latest block location covered by the digest.
   
       :rtype: dict
       :return: The response of the request.
       """
       result = qldb_client.get_revision(Name=ledger_name, BlockAddress=block_address, DocumentId=document_id,
                                         DigestTipAddress=digest_tip_address)
       return result
   
   
   def lookup_registration_for_vin(driver, vin):
       """
       Query revision history for a particular vehicle for verification.
   
       :type driver: :py:class:`pyqldb.driver.qldb_driver.QldbDriver`
       :param driver: An instance of the QldbDriver class.
   
       :type vin: str
       :param vin: VIN to query the revision history of a specific registration with.
   
       :rtype: :py:class:`pyqldb.cursor.buffered_cursor.BufferedCursor`
       :return: Cursor on the result set of the statement query.
       """
       logger.info("Querying the 'VehicleRegistration' table for VIN: {}...".format(vin))
       query = 'SELECT * FROM _ql_committed_VehicleRegistration WHERE data.VIN = ?'
       return driver.execute_lambda(lambda txn: txn.execute_statement(query, convert_object_to_ion(vin)))
   
   
   def verify_registration(driver, ledger_name, vin):
       """
       Verify each version of the registration for the given VIN.
   
       :type driver: :py:class:`pyqldb.driver.qldb_driver.QldbDriver`
       :param driver: An instance of the QldbDriver class.
   
       :type ledger_name: str
       :param ledger_name: The ledger to get digest from.
   
       :type vin: str
       :param vin: VIN to query the revision history of a specific registration with.
   
       :raises AssertionError: When verification failed.
       """
       logger.info("Let's verify the registration with VIN = {}, in ledger = {}.".format(vin, ledger_name))
       digest = get_digest_result(ledger_name)
       digest_bytes = digest.get('Digest')
       digest_tip_address = digest.get('DigestTipAddress')
   
       logger.info('Got a ledger digest: digest tip address = {}, digest = {}.'.format(
           value_holder_to_string(digest_tip_address.get('IonText')), to_base_64(digest_bytes)))
   
       logger.info('Querying the registration with VIN = {} to verify each version of the registration...'.format(vin))
       cursor = lookup_registration_for_vin(driver, vin)
       logger.info('Getting a proof for the document.')
   
       for row in cursor:
           block_address = row.get('blockAddress')
           document_id = row.get('metadata').get('id')
   
           result = get_revision(ledger_name, document_id, block_address_to_dictionary(block_address), digest_tip_address)
           revision = result.get('Revision').get('IonText')
           document_hash = loads(revision).get('hash')
   
           proof = result.get('Proof')
           logger.info('Got back a proof: {}.'.format(proof))
   
           verified = verify_document(document_hash, digest_bytes, proof)
           if not verified:
               raise AssertionError('Document revision is not verified.')
           else:
               logger.info('Success! The document is verified.')
   
           altered_document_hash = flip_random_bit(document_hash)
           logger.info("Flipping one bit in the document's hash and assert that the document is NOT verified. "
                       "The altered document hash is: {}.".format(to_base_64(altered_document_hash)))
           verified = verify_document(altered_document_hash, digest_bytes, proof)
           if verified:
               raise AssertionError('Expected altered document hash to not be verified against digest.')
           else:
               logger.info('Success! As expected flipping a bit in the document hash causes verification to fail.')
   
           logger.info('Finished verifying the registration with VIN = {} in ledger = {}.'.format(vin, ledger_name))
   
   
   def main(ledger_name=Constants.LEDGER_NAME):
       """
       Verify the integrity of a document revision in a QLDB ledger.
       """
       registration = SampleData.VEHICLE_REGISTRATION[0]
       vin = registration['VIN']
       try:
           with create_qldb_driver(ledger_name) as driver:
               verify_registration(driver, ledger_name, vin)
       except Exception as e:
           logger.exception('Unable to verify revision.')
           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 logging import basicConfig, getLogger, INFO
   
   from amazon.ion.simpleion import loads
   from boto3 import client
   
   from pyqldbsamples.constants import Constants
   from pyqldbsamples.get_digest import get_digest_result
   from pyqldbsamples.model.sample_data import SampleData, convert_object_to_ion
   from pyqldbsamples.qldb.block_address import block_address_to_dictionary
   from pyqldbsamples.verifier import verify_document, flip_random_bit, to_base_64
   from pyqldbsamples.connect_to_ledger import create_qldb_session
   from pyqldbsamples.qldb.qldb_string_utils import value_holder_to_string
   
   logger = getLogger(__name__)
   basicConfig(level=INFO)
   qldb_client = client('qldb')
   
   
   def get_revision(ledger_name, document_id, block_address, digest_tip_address):
       """
       Get the revision data object for a specified document ID and block address.
       Also returns a proof of the specified revision for verification.
   
       :type ledger_name: str
       :param ledger_name: Name of the ledger containing the document to query.
   
       :type document_id: str
       :param document_id: Unique ID for the document to be verified, contained in the committed view of the document.
   
       :type block_address: dict
       :param block_address: The location of the block to request.
   
       :type digest_tip_address: dict
       :param digest_tip_address: The latest block location covered by the digest.
   
       :rtype: dict
       :return: The response of the request.
       """
       result = qldb_client.get_revision(Name=ledger_name, BlockAddress=block_address, DocumentId=document_id,
                                         DigestTipAddress=digest_tip_address)
       return result
   
   
   def lookup_registration_for_vin(qldb_session, vin):
       """
       Query revision history for a particular vehicle for verification.
   
       :type qldb_session: :py:class:`pyqldb.session.qldb_session.QldbSession`
       :param qldb_session: An instance of the QldbSession class.
   
       :type vin: str
       :param vin: VIN to query the revision history of a specific registration with.
   
       :rtype: :py:class:`pyqldb.cursor.buffered_cursor.BufferedCursor`
       :return: Cursor on the result set of the statement query.
       """
       logger.info("Querying the 'VehicleRegistration' table for VIN: {}...".format(vin))
       query = 'SELECT * FROM _ql_committed_VehicleRegistration WHERE data.VIN = ?'
       parameters = [convert_object_to_ion(vin)]
       cursor = qldb_session.execute_statement(query, parameters)
       return cursor
   
   
   def verify_registration(qldb_session, ledger_name, vin):
       """
       Verify each version of the registration for the given VIN.
   
       :type qldb_session: :py:class:`pyqldb.session.qldb_session.QldbSession`
       :param qldb_session: An instance of the QldbSession class.
   
       :type ledger_name: str
       :param ledger_name: The ledger to get digest from.
   
       :type vin: str
       :param vin: VIN to query the revision history of a specific registration with.
   
       :raises AssertionError: When verification failed.
       """
       logger.info("Let's verify the registration with VIN = {}, in ledger = {}.".format(vin, ledger_name))
       digest = get_digest_result(ledger_name)
       digest_bytes = digest.get('Digest')
       digest_tip_address = digest.get('DigestTipAddress')
   
       logger.info('Got a ledger digest: digest tip address = {}, digest = {}.'.format(
           value_holder_to_string(digest_tip_address.get('IonText')), to_base_64(digest_bytes)))
   
       logger.info('Querying the registration with VIN = {} to verify each version of the registration...'.format(vin))
       cursor = lookup_registration_for_vin(qldb_session, vin)
       logger.info('Getting a proof for the document.')
   
       for row in cursor:
           block_address = row.get('blockAddress')
           document_id = row.get('metadata').get('id')
   
           result = get_revision(ledger_name, document_id, block_address_to_dictionary(block_address), digest_tip_address)
           revision = result.get('Revision').get('IonText')
           document_hash = loads(revision).get('hash')
   
           proof = result.get('Proof')
           logger.info('Got back a proof: {}.'.format(proof))
   
           verified = verify_document(document_hash, digest_bytes, proof)
           if not verified:
               raise AssertionError('Document revision is not verified.')
           else:
               logger.info('Success! The document is verified.')
   
           altered_document_hash = flip_random_bit(document_hash)
           logger.info("Flipping one bit in the document's hash and assert that the document is NOT verified. "
                       "The altered document hash is: {}.".format(to_base_64(altered_document_hash)))
           verified = verify_document(altered_document_hash, digest_bytes, proof)
           if verified:
               raise AssertionError('Expected altered document hash to not be verified against digest.')
           else:
               logger.info('Success! As expected flipping a bit in the document hash causes verification to fail.')
   
           logger.info('Finished verifying the registration with VIN = {} in ledger = {}.'.format(vin, ledger_name))
   
   
   if __name__ == '__main__':
       """
       Verify the integrity of a document revision in a QLDB ledger.
       """
       registration = SampleData.VEHICLE_REGISTRATION[0]
       vin = registration['VIN']
       try:
           with create_qldb_session() as session:
               verify_registration(session, Constants.LEDGER_NAME, vin)
       except Exception:
           logger.exception('Unable to verify revision.')
   ```

------
**Nota**  
Dopo che la `get_revision` funzione ha restituito una bozza per la revisione del documento specificata, questo programma utilizza un'API lato client per verificare tale revisione.

1. Per eseguire il programma, immetti il comando seguente:

   ```
   python get_revision.py
   ```

Se non hai più bisogno di usare il `vehicle-registration` libro mastro, procedi con. [Passaggio 8 (opzionale): Pulisci le risorse](getting-started.python.step-8.md)

# Passaggio 8 (opzionale): Pulisci le risorse
<a name="getting-started.python.step-8"></a>

**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/).

Puoi `vehicle-registration` continuare a utilizzare il registro. Tuttavia, se non è più necessario, è necessario eliminarlo.

**Per eliminare il registro**

1. Utilizzate il seguente programma (`delete_ledger.py`) per eliminare il `vehicle-registration` registro e tutto il suo contenuto.

   ```
   # 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 logging import basicConfig, getLogger, INFO
   from time import sleep
   
   from boto3 import client
   
   from pyqldbsamples.constants import Constants
   from pyqldbsamples.describe_ledger import describe_ledger
   
   logger = getLogger(__name__)
   basicConfig(level=INFO)
   qldb_client = client('qldb')
   
   LEDGER_DELETION_POLL_PERIOD_SEC = 20
   
   
   def delete_ledger(ledger_name):
       """
       Send a request to QLDB to delete the specified ledger.
   
       :type ledger_name: str
       :param ledger_name: Name for the ledger to be deleted.
   
       :rtype: dict
       :return: Result from the request.
       """
       logger.info('Attempting to delete the ledger with name: {}...'.format(ledger_name))
       result = qldb_client.delete_ledger(Name=ledger_name)
       logger.info('Success.')
       return result
   
   
   def wait_for_deleted(ledger_name):
       """
       Wait for the ledger to be deleted.
   
       :type ledger_name: str
       :param ledger_name: The ledger to check on.
       """
       logger.info('Waiting for the ledger to be deleted...')
       while True:
           try:
               describe_ledger(ledger_name)
               logger.info('The ledger is still being deleted. Please wait...')
               sleep(LEDGER_DELETION_POLL_PERIOD_SEC)
           except qldb_client.exceptions.ResourceNotFoundException:
               logger.info('Success. The ledger is deleted.')
               break
   
   
   def set_deletion_protection(ledger_name, deletion_protection):
       """
       Update an existing ledger's deletion protection.
   
       :type ledger_name: str
       :param ledger_name: Name of the ledger to update.
   
       :type deletion_protection: bool
       :param deletion_protection: Enable or disable the deletion protection.
   
       :rtype: dict
       :return: Result from the request.
       """
       logger.info("Let's set deletion protection to {} for the ledger with name {}.".format(deletion_protection,
                                                                                             ledger_name))
       result = qldb_client.update_ledger(Name=ledger_name, DeletionProtection=deletion_protection)
       logger.info('Success. Ledger updated: {}'.format(result))
   
   
   def main(ledger_name=Constants.LEDGER_NAME):
       """
       Delete a ledger.
       """
       try:
           set_deletion_protection(ledger_name, False)
           delete_ledger(ledger_name)
           wait_for_deleted(ledger_name)
       except Exception as e:
           logger.exception('Unable to delete the ledger.')
           raise e
   
   
   if __name__ == '__main__':
       main()
   ```
**Nota**  
Se la protezione da eliminazione è abilitata per il registro, devi prima disabilitarla prima di poter eliminare il registro utilizzando l'API QLDB.

   Il `delete_ledger.py` file dipende anche dal seguente programma (). `describe_ledger.py`

   ```
   # 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 logging import basicConfig, getLogger, INFO
   
   from boto3 import client
   
   from pyqldbsamples.constants import Constants
   
   logger = getLogger(__name__)
   basicConfig(level=INFO)
   qldb_client = client('qldb')
   
   
   def describe_ledger(ledger_name):
       """
       Describe a ledger.
   
       :type ledger_name: str
       :param ledger_name: Name of the ledger to describe.
       """
       logger.info('describe ledger with name: {}.'.format(ledger_name))
       result = qldb_client.describe_ledger(Name=ledger_name)
       result.pop('ResponseMetadata')
       logger.info('Success. Ledger description: {}.'.format(result))
       return result
   
   
   def main(ledger_name=Constants.LEDGER_NAME):
       """
       Describe a QLDB ledger.
       """
       try:
           describe_ledger(ledger_name)
       except Exception as e:
           logger.exception('Unable to describe a ledger.')
           raise e
   
   
   if __name__ == '__main__':
       main()
   ```

1. Per eseguire il programma, immetti il comando seguente:

   ```
   python delete_ledger.py
   ```