Lire les lignes avec un préfixe

Créer une requête avec un préfixe.

Pages de documentation incluant cet exemple de code

Pour afficher l'exemple de code utilisé en contexte, consultez la documentation suivante :

Exemple de code

C#

Pour savoir comment installer et utiliser la bibliothèque cliente pour Bigtable, consultez la section Bibliothèques clientes Bigtable.


/// <summary>
/// /// Reads rows starting with a prefix from an existing table.
///</summary>
/// <param name="projectId">Your Google Cloud Project ID.</param>
/// <param name="instanceId">Your Google Cloud Bigtable Instance ID.</param>
/// <param name="tableId">Your Google Cloud Bigtable table ID.</param>
public string readPrefix(string projectId = "YOUR-PROJECT-ID", string instanceId = "YOUR-INSTANCE-ID", string tableId = "YOUR-TABLE-ID")
{
    BigtableClient bigtableClient = BigtableClient.Create();
    TableName tableName = new TableName(projectId, instanceId, tableId);

    String prefix = "phone";
    Char prefixEndChar = prefix[prefix.Length - 1];
    prefixEndChar++;
    String end = prefix.Substring(0, prefix.Length - 1) + prefixEndChar;
    RowSet rowSet = RowSet.FromRowRanges(RowRange.Closed(prefix, end));
    ReadRowsStream readRowsStream = bigtableClient.ReadRows(tableName, rowSet);

    string result = "";
    readRowsStream.ForEach(row => result += printRow(row));

    return result;
}

C++

Pour savoir comment installer et utiliser la bibliothèque cliente pour Bigtable, consultez la section Bibliothèques clientes Bigtable.

namespace cbt = ::google::cloud::bigtable;
using ::google::cloud::StatusOr;
[](cbt::Table table) {
  // Read and print the rows.
  for (StatusOr<cbt::Row> const& row : table.ReadRows(
           cbt::RowRange::Prefix("phone"), cbt::Filter::PassAllFilter())) {
    if (!row) throw std::runtime_error(row.status().message());
    PrintRow(*row);
  }
}

Go

Pour savoir comment installer et utiliser la bibliothèque cliente pour Bigtable, consultez la section Bibliothèques clientes Bigtable.

func readPrefix(w io.Writer, projectID, instanceID string, tableName string) error {
	// projectID := "my-project-id"
	// instanceID := "my-instance-id"
	// tableName := "mobile-time-series"

	ctx := context.Background()
	client, err := bigtable.NewClient(ctx, projectID, instanceID)
	if err != nil {
		return fmt.Errorf("bigtable.NewAdminClient: %v", err)
	}
	tbl := client.Open(tableName)
	err = tbl.ReadRows(ctx, bigtable.PrefixRange("phone#"),
		func(row bigtable.Row) bool {
			printRow(w, row)
			return true
		})

	if err = client.Close(); err != nil {
		return fmt.Errorf("client.Close(): %v", err)
	}

	return nil
}

Java

Pour savoir comment installer et utiliser la bibliothèque cliente pour Bigtable, consultez la section Bibliothèques clientes Bigtable.

public static void readPrefix() {
  // TODO(developer): Replace these variables before running the sample.
  String projectId = "my-project-id";
  String instanceId = "my-instance-id";
  String tableId = "mobile-time-series";
  readPrefix(projectId, instanceId, tableId);
}

public static void readPrefix(String projectId, String instanceId, String tableId) {
  // Initialize client that will be used to send requests. This client only needs to be created
  // once, and can be reused for multiple requests. After completing all of your requests, call
  // the "close" method on the client to safely clean up any remaining background resources.
  try (BigtableDataClient dataClient = BigtableDataClient.create(projectId, instanceId)) {
    Query query = Query.create(tableId).prefix("phone");
    ServerStream<Row> rows = dataClient.readRows(query);
    for (Row row : rows) {
      printRow(row);
    }
  } catch (IOException e) {
    System.out.println(
        "Unable to initialize service client, as a network error occurred: \n" + e.toString());
  }
}

Node.js

Pour savoir comment installer et utiliser la bibliothèque cliente pour Bigtable, consultez la section Bibliothèques clientes Bigtable.

const prefix = 'phone#';

await table
  .createReadStream({
    prefix,
  })
  .on('error', err => {
    // Handle the error.
    console.log(err);
  })
  .on('data', row => printRow(row.id, row.data))
  .on('end', () => {
    // All rows retrieved.
  });

PHP

Pour savoir comment installer et utiliser la bibliothèque cliente pour Bigtable, consultez la section Bibliothèques clientes Bigtable.

use Google\Cloud\Bigtable\BigtableClient;

/**
 * Read using a row key prefix
 * @param string $projectId The Google Cloud project ID
 * @param string $instanceId The ID of the Bigtable instance
 * @param string $tableId The ID of the table to read from
 */
function read_prefix(
    string $projectId,
    string $instanceId,
    string $tableId
): void {
    // Connect to an existing table with an existing instance.
    $dataClient = new BigtableClient([
        'projectId' => $projectId,
    ]);
    $table = $dataClient->table($instanceId, $tableId);

    $prefix = 'phone#';
    $end = $prefix;
    // Increment the last character of the prefix so the filter matches everything in between
    $end[-1] = chr(
        ord($end[-1]) + 1
    );

    $rows = $table->readRows([
        'rowRanges' => [
            [
                'startKeyClosed' => $prefix,
                'endKeyClosed' => $end,
            ]
        ]
    ]);

    foreach ($rows as $key => $row) {
        print_row($key, $row);
    }
}

Python

Pour savoir comment installer et utiliser la bibliothèque cliente pour Bigtable, consultez la section Bibliothèques clientes Bigtable.

def read_prefix(project_id, instance_id, table_id):
    client = bigtable.Client(project=project_id, admin=True)
    instance = client.instance(instance_id)
    table = instance.table(table_id)
    prefix = "phone#"
    end_key = prefix[:-1] + chr(ord(prefix[-1]) + 1)

    row_set = RowSet()
    row_set.add_row_range_from_keys(prefix.encode("utf-8"),
                                    end_key.encode("utf-8"))

    rows = table.read_rows(row_set=row_set)
    for row in rows:
        print_row(row)

Ruby

Pour savoir comment installer et utiliser la bibliothèque cliente pour Bigtable, consultez la section Bibliothèques clientes Bigtable.

# instance_id = "my-instance"
# table_id    = "my-table"
bigtable = Google::Cloud::Bigtable.new
table = bigtable.table instance_id, table_id

prefix = "phone#"
range = table.new_row_range.between prefix, prefix.next
table.read_rows(ranges: range).each do |row|
  print_row row
end

Étape suivante

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