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Agrega columnas TIMESTAMP

Agrega una columna TIMESTAMP para actualizar un esquema.

Muestra de código

C++

Para obtener información sobre cómo instalar y usar la biblioteca cliente de Spanner, consulta Bibliotecas cliente de Spanner.

Para autenticarte en Spanner, configura las credenciales predeterminadas de la aplicación. Si deseas obtener más información, consulta Configura la autenticación para un entorno de desarrollo local.

void AddTimestampColumn(
    google::cloud::spanner_admin::DatabaseAdminClient client,
    std::string const& project_id, std::string const& instance_id,
    std::string const& database_id) {
  google::cloud::spanner::Database database(project_id, instance_id,
                                            database_id);
  auto metadata =
      client
          .UpdateDatabaseDdl(
              database.FullName(),
              {"ALTER TABLE Albums ADD COLUMN LastUpdateTime TIMESTAMP "
               "OPTIONS (allow_commit_timestamp=true)"})
          .get();
  google::cloud::spanner_testing::LogUpdateDatabaseDdl(  //! TODO(#4758)
      client, database, metadata.status());              //! TODO(#4758)
  if (!metadata) throw std::move(metadata).status();
  std::cout << "Added LastUpdateTime column\n";
}

C#

Para obtener información sobre cómo instalar y usar la biblioteca cliente de Spanner, consulta Bibliotecas cliente de Spanner.


using Google.Cloud.Spanner.Data;
using System;
using System.Threading.Tasks;

public class AddCommitTimestampAsyncSample
{
    public async Task AddCommitTimestampAsync(string projectId, string instanceId, string databaseId)
    {
        string connectionString = $"Data Source=projects/{projectId}/instances/{instanceId}/databases/{databaseId}";
        string alterStatement = "ALTER TABLE Albums ADD COLUMN LastUpdateTime TIMESTAMP OPTIONS (allow_commit_timestamp=true)";
        using var connection = new SpannerConnection(connectionString);
        var updateCmd = connection.CreateDdlCommand(alterStatement);
        await updateCmd.ExecuteNonQueryAsync();
        Console.WriteLine("Added LastUpdateTime as a commit timestamp column in Albums table.");
    }
}

Go

Para obtener información sobre cómo instalar y usar la biblioteca cliente de Spanner, consulta Bibliotecas cliente de Spanner.


import (
	"context"
	"fmt"
	"io"

	database "cloud.google.com/go/spanner/admin/database/apiv1"
	adminpb "cloud.google.com/go/spanner/admin/database/apiv1/databasepb"
)

func addCommitTimestamp(ctx context.Context, w io.Writer, db string) error {
	adminClient, err := database.NewDatabaseAdminClient(ctx)
	if err != nil {
		return err
	}
	defer adminClient.Close()

	op, err := adminClient.UpdateDatabaseDdl(ctx, &adminpb.UpdateDatabaseDdlRequest{
		Database: db,
		Statements: []string{
			"ALTER TABLE Albums ADD COLUMN LastUpdateTime TIMESTAMP " +
				"OPTIONS (allow_commit_timestamp=true)",
		},
	})
	if err != nil {
		return err
	}
	if err := op.Wait(ctx); err != nil {
		return err
	}
	fmt.Fprintf(w, "Added LastUpdateTime as a commit timestamp column in Albums table\n")
	return nil
}

Java

Para obtener información sobre cómo instalar y usar la biblioteca cliente de Spanner, consulta Bibliotecas cliente de Spanner.

static void addCommitTimestamp(DatabaseAdminClient adminClient, DatabaseId dbId) {
  OperationFuture<Void, UpdateDatabaseDdlMetadata> op =
      adminClient.updateDatabaseDdl(
          dbId.getInstanceId().getInstance(),
          dbId.getDatabase(),
          Arrays.asList(
              "ALTER TABLE Albums ADD COLUMN LastUpdateTime TIMESTAMP "
                  + "OPTIONS (allow_commit_timestamp=true)"),
          null);
  try {
    // Initiate the request which returns an OperationFuture.
    op.get();
    System.out.println("Added LastUpdateTime as a commit timestamp column in Albums table.");
  } catch (ExecutionException e) {
    // If the operation failed during execution, expose the cause.
    throw (SpannerException) e.getCause();
  } catch (InterruptedException e) {
    // Throw when a thread is waiting, sleeping, or otherwise occupied,
    // and the thread is interrupted, either before or during the activity.
    throw SpannerExceptionFactory.propagateInterrupt(e);
  }
}

Node.js

Para obtener información sobre cómo instalar y usar la biblioteca cliente de Spanner, consulta Bibliotecas cliente de Spanner.

// Imports the Google Cloud client library
const {Spanner} = require('@google-cloud/spanner');

/**
 * TODO(developer): Uncomment the following lines before running the sample.
 */
// const projectId = 'my-project-id';
// const instanceId = 'my-instance';
// const databaseId = 'my-database';

// Creates a client
const spanner = new Spanner({
  projectId: projectId,
});

// Gets a reference to a Cloud Spanner Database Admin Client object
const databaseAdminClient = spanner.getDatabaseAdminClient();

const request = [
  `ALTER TABLE Albums ADD COLUMN LastUpdateTime TIMESTAMP OPTIONS
  (allow_commit_timestamp=true)`,
];

// Adds a new commit timestamp column to the Albums table
try {
  const [operation] = await databaseAdminClient.updateDatabaseDdl({
    database: databaseAdminClient.databasePath(
      projectId,
      instanceId,
      databaseId
    ),
    statements: request,
  });

  console.log('Waiting for operation to complete...');

  await operation.promise();

  console.log(
    'Added LastUpdateTime as a commit timestamp column in Albums table.'
  );
} catch (err) {
  console.error('ERROR:', err);
} finally {
  // Close the spanner client when finished.
  // The databaseAdminClient does not require explicit closure. The closure of the Spanner client will automatically close the databaseAdminClient.
  spanner.close();
}

PHP

Para obtener información sobre cómo instalar y usar la biblioteca cliente de Spanner, consulta Bibliotecas cliente de Spanner.

use Google\Cloud\Spanner\SpannerClient;

/**
 * Adds a commit timestamp column to a table.
 * Example:
 * ```
 * add_timestamp_column($instanceId, $databaseId);
 * ```
 *
 * @param string $instanceId The Spanner instance ID.
 * @param string $databaseId The Spanner database ID.
 */
function add_timestamp_column(string $instanceId, string $databaseId): void
{
    $spanner = new SpannerClient();
    $instance = $spanner->instance($instanceId);
    $database = $instance->database($databaseId);

    $operation = $database->updateDdl(
        'ALTER TABLE Albums ADD COLUMN LastUpdateTime TIMESTAMP OPTIONS (allow_commit_timestamp=true)'
    );

    print('Waiting for operation to complete...' . PHP_EOL);
    $operation->pollUntilComplete();

    printf('Added LastUpdateTime as a commit timestamp column in Albums table' . PHP_EOL);
}

Python

Para obtener información sobre cómo instalar y usar la biblioteca cliente de Spanner, consulta Bibliotecas cliente de Spanner.

def add_timestamp_column(instance_id, database_id):
    """Adds a new TIMESTAMP column to the Albums table in the example database."""

    from google.cloud.spanner_admin_database_v1.types import \
        spanner_database_admin

    spanner_client = spanner.Client()
    database_admin_api = spanner_client.database_admin_api

    request = spanner_database_admin.UpdateDatabaseDdlRequest(
        database=database_admin_api.database_path(
            spanner_client.project, instance_id, database_id
        ),
        statements=[
            "ALTER TABLE Albums ADD COLUMN LastUpdateTime TIMESTAMP "
            "OPTIONS(allow_commit_timestamp=true)"
        ],
    )

    operation = database_admin_api.update_database_ddl(request)

    print("Waiting for operation to complete...")
    operation.result(OPERATION_TIMEOUT_SECONDS)

    print(
        'Altered table "Albums" on database {} on instance {}.'.format(
            database_id, instance_id
        )
    )

Ruby

Para obtener información sobre cómo instalar y usar la biblioteca cliente de Spanner, consulta Bibliotecas cliente de Spanner.

# project_id  = "Your Google Cloud project ID"
# instance_id = "Your Spanner instance ID"
# database_id = "Your Spanner database ID"

require "google/cloud/spanner"
require "google/cloud/spanner/admin/database"

database_admin_client = Google::Cloud::Spanner::Admin::Database.database_admin

db_path = database_admin_client.database_path project: project_id,
                                              instance: instance_id,
                                              database: database_id

job = database_admin_client.update_database_ddl database: db_path,
                                                statements: [
                                                  "ALTER TABLE Albums ADD COLUMN LastUpdateTime TIMESTAMP
   OPTIONS (allow_commit_timestamp=true)"
                                                ]

puts "Waiting for database update to complete"

job.wait_until_done!

puts "Added the LastUpdateTime as a commit timestamp column in Albums table"

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