Langkah 6: Lihat riwayat revisi untuk dokumen

penting

Pemberitahuan akhir dukungan: Pelanggan yang ada akan dapat menggunakan Amazon QLDB hingga akhir dukungan pada 07/31/2025. Untuk detail selengkapnya, lihat Memigrasi QLDB Buku Besar Amazon ke Amazon Aurora Postgre. SQL

Setelah memodifikasi data registrasi untuk kendaraan pada langkah sebelumnya, Anda dapat menanyakan riwayat semua pemilik terdaftar dan bidang yang diperbarui lainnya. Pada langkah ini, Anda menanyakan riwayat revisi dokumen dalam VehicleRegistration tabel di vehicle-registration buku besar Anda.

Untuk melihat riwayat revisi

Tinjau program berikut (QueryHistory.java).

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.
 */

package software.amazon.qldb.tutorial;

import java.io.IOException;
import java.time.Instant;
import java.time.temporal.ChronoUnit;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.amazon.ion.IonValue;

import software.amazon.qldb.Result;
import software.amazon.qldb.TransactionExecutor;
import software.amazon.qldb.tutorial.model.SampleData;
import software.amazon.qldb.tutorial.model.VehicleRegistration;

/**
 * Query a table's history for a particular set of documents.
 *
 * This code expects that you have AWS credentials setup per:
 * http://docs.aws.amazon.com/java-sdk/latest/developer-guide/setup-credentials.html
 */
public final class QueryHistory {
    public static final Logger log = LoggerFactory.getLogger(QueryHistory.class);
    private static final int THREE_MONTHS = 90;

    private QueryHistory() { }

    /**
     * In this example, query the 'VehicleRegistration' history table to find all previous primary owners for a VIN.
     *
     * @param txn
     *              The {@link TransactionExecutor} for lambda execute.
     * @param vin
     *              VIN to find previous primary owners for.
     * @param query
     *              The query to find previous primary owners.
     * @throws IllegalStateException if failed to convert document ID to an {@link IonValue}.
     */
    public static void previousPrimaryOwners(final TransactionExecutor txn, final String vin, final String query) {
        try {
            final String docId = VehicleRegistration.getDocumentIdByVin(txn, vin);

            log.info("Querying the 'VehicleRegistration' table's history using VIN: {}...", vin);
            final Result result = txn.execute(query, Constants.MAPPER.writeValueAsIonValue(docId));
            ScanTable.printDocuments(result);
        } catch (IOException ioe) {
            throw new IllegalStateException(ioe);
        }
    }

    public static void main(final String... args) {
        final String threeMonthsAgo = Instant.now().minus(THREE_MONTHS, ChronoUnit.DAYS).toString();
        final String query = String.format("SELECT data.Owners.PrimaryOwner, metadata.version "
                                           + "FROM history(VehicleRegistration, `%s`) "
                                           + "AS h WHERE h.metadata.id = ?", threeMonthsAgo);
        ConnectToLedger.getDriver().execute(txn -> {
            final String vin = SampleData.VEHICLES.get(0).getVin();
            previousPrimaryOwners(txn, vin, query);
        });
        log.info("Successfully queried history.");
    }
}

1.x


/*
 * Copyright 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.
 */

package software.amazon.qldb.tutorial;

import com.amazon.ion.IonValue;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import software.amazon.qldb.QldbSession;
import software.amazon.qldb.Result;
import software.amazon.qldb.TransactionExecutor;
import software.amazon.qldb.tutorial.model.SampleData;
import software.amazon.qldb.tutorial.model.VehicleRegistration;

import java.io.IOException;
import java.time.Instant;
import java.time.temporal.ChronoUnit;
import java.util.Collections;
import java.util.List;

/**
 * Query a table's history for a particular set of documents.
 *
 * This code expects that you have AWS credentials setup per:
 * http://docs.aws.amazon.com/java-sdk/latest/developer-guide/setup-credentials.html
 */
public final class QueryHistory {
    public static final Logger log = LoggerFactory.getLogger(QueryHistory.class);
    private static final int THREE_MONTHS = 90;

    private QueryHistory() { }

    /**
     * In this example, query the 'VehicleRegistration' history table to find all previous primary owners for a VIN.
     *
     * @param txn
     *              The {@link TransactionExecutor} for lambda execute.
     * @param vin
     *              VIN to find previous primary owners for.
     * @param query
     *              The query to find previous primary owners.
     * @throws IllegalStateException if failed to convert document ID to an {@link IonValue}.
     */
    public static void previousPrimaryOwners(final TransactionExecutor txn, final String vin, final String query) {
        try {
            final String docId = VehicleRegistration.getDocumentIdByVin(txn, vin);
            final List<IonValue> parameters = Collections.singletonList(Constants.MAPPER.writeValueAsIonValue(docId));
            log.info("Querying the 'VehicleRegistration' table's history using VIN: {}...", vin);
            final Result result = txn.execute(query, parameters);
            ScanTable.printDocuments(result);
        } catch (IOException ioe) {
            throw new IllegalStateException(ioe);
        }
    }

    public static void main(final String... args) {
        final String threeMonthsAgo = Instant.now().minus(THREE_MONTHS, ChronoUnit.DAYS).toString();
        final String query = String.format("SELECT data.Owners.PrimaryOwner, metadata.version "
                                           + "FROM history(VehicleRegistration, `%s`) "
                                           + "AS h WHERE h.metadata.id = ?", threeMonthsAgo);
        ConnectToLedger.getDriver().execute(txn -> {
            final String vin = SampleData.VEHICLES.get(0).getVin();
            previousPrimaryOwners(txn, vin, query);
        }, (retryAttempt) -> log.info("Retrying due to OCC conflict..."));
        log.info("Successfully queried history.");
    }
}

catatan

Anda dapat melihat riwayat revisi dokumen dengan menanyakan built-in Fungsi sejarah dalam sintaks berikut.


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

Waktu mulai dan akhir waktu keduanya opsional. Itu adalah nilai literal Amazon Ion yang dapat dilambangkan dengan backticks (). `...` Untuk mempelajari selengkapnya, lihat Meminta Ion dengan PartiQL di Amazon QLDB.
Sebagai praktik terbaik, kualifikasikan kueri riwayat dengan rentang tanggal (waktu mulai dan akhir waktu) dan ID dokumen (). metadata.id QLDBmemproses SELECT kueri dalam transaksi, yang tunduk pada batas waktu tunggu transaksi.

QLDBriwayat diindeks oleh ID dokumen, dan Anda tidak dapat membuat indeks riwayat tambahan saat ini. Pertanyaan sejarah yang mencakup waktu mulai dan waktu akhir mendapatkan manfaat dari kualifikasi rentang tanggal.

Kompilasi dan jalankan QueryHistory.java program untuk menanyakan riwayat revisi VehicleRegistration dokumen dengan. VIN 1N4AL11D75C109151

Untuk memverifikasi revisi dokumen secara kriptografis di vehicle-registration buku besar, lanjutkan ke. Langkah 7: Verifikasi dokumen dalam buku besar

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Konvensi Dokumen

Langkah 5: Ubah dokumen

Langkah 7: Verifikasi dokumen