Lettura utilizzando un filtro per un intervallo di timestamp

Mantieni tutto organizzato con le raccolte Salva e classifica i contenuti in base alle tue preferenze.

Crea un filtro limitatore su un intervallo di timestamp delle celle.

Per saperne di più

Per la documentazione dettagliata che include questo esempio di codice, vedi quanto segue:

Esempio di codice

C++

Per scoprire come installare e utilizzare la libreria client per Bigtable, consulta Librerie client Bigtable. 

namespace cbt = ::google::cloud::bigtable;
using ::google::cloud::StatusOr;
[](cbt::Table table) {
  cbt::Filter filter =
      cbt::Filter::TimestampRange(microseconds(1000), milliseconds(2));
  // Read and print the rows.
  for (auto& row :
       table.ReadRows(cbt::RowSet(cbt::RowRange::InfiniteRange()), filter)) {
    if (!row) throw std::move(row).status();
    std::cout << row->row_key() << " = ";
    for (auto const& cell : row->cells()) {
      std::cout << "[" << cell.family_name() << ", "
                << cell.column_qualifier() << ", " << cell.value() << "],";
    }
    std::cout << "\n";
  }
}

C#

Per scoprire come installare e utilizzare la libreria client per Bigtable, consulta Librerie client Bigtable. 

    /// <summary>
    /// /// Read using a timestamp range filter 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 filterLimitTimestampRange(
String projectId, String instanceId, String tableId)
    {
        BigtableVersion timestamp_minus_hr = new BigtableVersion(new DateTime(2020, 1, 10, 13, 0, 0, DateTimeKind.Utc));

        // A filter that matches cells whose timestamp is from an hour ago or earlier
        RowFilter filter = RowFilters.TimestampRange(new DateTime(0), timestamp_minus_hr.ToDateTime());
        return readFilter(projectId, instanceId, tableId, filter);
    }

Go

Per scoprire come installare e utilizzare la libreria client per Bigtable, consulta Librerie client Bigtable. 

func filterLimitTimestampRange(w io.Writer, projectID, instanceID string, tableName string) error {
	startTime := time.Unix(0, 0)
	endTime := time.Now().Add(-1 * time.Hour)
	filter := bigtable.TimestampRangeFilter(startTime, endTime)

	return readWithFilter(w, projectID, instanceID, tableName, filter)
}

Java

Per scoprire come installare e utilizzare la libreria client per Bigtable, consulta Librerie client Bigtable. 

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

public static void filterLimitTimestampRange(
    String projectId, String instanceId, String tableId) {
  // Get a time representing one hour ago
  long timestamp = Instant.now().minus(1, ChronoUnit.HOURS).toEpochMilli() * 1000;

  // A filter that matches cells whose timestamp is from an hour ago or earlier
  Filter filter = FILTERS.timestamp().range().startClosed(0L).endOpen(timestamp);
  readFilter(projectId, instanceId, tableId, filter);
}

Node.js

Per scoprire come installare e utilizzare la libreria client per Bigtable, consulta Librerie client Bigtable. 

const start = 0;
const end = new Date(2019, 5, 1);
end.setUTCHours(0);
const filter = {
  time: {
    start,
    end,
  },
};
readWithFilter(filter);

PHP

Per scoprire come installare e utilizzare la libreria client per Bigtable, consulta Librerie client Bigtable. 

use Google\Cloud\Bigtable\BigtableClient;
use Google\Cloud\Bigtable\Filter;

/**
 * Create a limiting filter on a range of cell timestamps
 *
 * @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
 * @param int $endTime The timestamp upto which you want to fetch the rows
 */
function filter_limit_timestamp_range(
    string $projectId,
    string $instanceId,
    string $tableId,
    int $endTime = null
): void {
    // Connect to an existing table with an existing instance.
    $dataClient = new BigtableClient([
        'projectId' => $projectId,
    ]);
    $table = $dataClient->table($instanceId, $tableId);
    $endTime = is_null($endTime) ? (time() - 60 * 60) * 1000 * 1000 : $endTime;

    $start = 0;
    $filter = Filter::timestamp()
        ->range()
        ->startClosed($start)
        ->endOpen($endTime);

    $rows = $table->readRows([
        'filter' => $filter
    ]);

    foreach ($rows as $key => $row) {
        // The "print_row" helper function is defined in https://cloud.google.com/bigtable/docs/samples/bigtable-reads-print
        print_row($key, $row);
    }
}

Python

Per scoprire come installare e utilizzare la libreria client per Bigtable, consulta Librerie client Bigtable. 

def filter_limit_timestamp_range(project_id, instance_id, table_id):
    client = bigtable.Client(project=project_id, admin=True)
    instance = client.instance(instance_id)
    table = instance.table(table_id)

    end = datetime.datetime(2019, 5, 1)

    rows = table.read_rows(
        filter_=row_filters.TimestampRangeFilter(row_filters.TimestampRange(end=end))
    )
    for row in rows:
        print_row(row)

Ruby

Per scoprire come installare e utilizzare la libreria client per Bigtable, consulta Librerie client Bigtable. 

# instance_id = "my-instance"
# table_id    = "my-table"
timestamp_minus_hr = (Time.now.to_f * 1_000_000).round(-3) - (60 * 60 * 1000 * 1000)
puts timestamp_minus_hr
filter = Google::Cloud::Bigtable::RowFilter.timestamp_range from: 0, to: timestamp_minus_hr

read_with_filter instance_id, table_id, filter

Passaggi successivi

Per cercare e filtrare esempi di codice per altri prodotti Google Cloud, consulta il browser di esempio Google Cloud.