Données de mise à jour LMD avec STRUCT

Mettre à jour des données à l'aide du langage LMD avec un objet STRUCT.

En savoir plus

Pour obtenir une documentation détaillée incluant cet exemple de code, consultez les articles suivants :

Exemple de code

C++

Pour savoir comment installer et utiliser la bibliothèque cliente pour Spanner, consultez la page Bibliothèques clientes Spanner.

Pour vous authentifier auprès de Spanner, configurez les Identifiants par défaut de l'application. Pour en savoir plus, consultez Configurer l'authentification pour un environnement de développement local.

void DmlStructs(google::cloud::spanner::Client client) {
  namespace spanner = ::google::cloud::spanner;
  std::int64_t rows_modified = 0;
  auto commit_result =
      client.Commit([&client, &rows_modified](spanner::Transaction const& txn)
                        -> google::cloud::StatusOr<spanner::Mutations> {
        auto singer_info = std::make_tuple("Marc", "Richards");
        auto sql = spanner::SqlStatement(
            "UPDATE Singers SET FirstName = 'Keith' WHERE "
            "STRUCT<FirstName String, LastName String>(FirstName, LastName) "
            "= @name",
            {{"name", spanner::Value(std::move(singer_info))}});
        auto dml_result = client.ExecuteDml(txn, std::move(sql));
        if (!dml_result) return std::move(dml_result).status();
        rows_modified = dml_result->RowsModified();
        return spanner::Mutations{};
      });
  if (!commit_result) throw std::move(commit_result).status();
  std::cout << rows_modified
            << " update was successful [spanner_dml_structs]\n";
}

C#

Pour savoir comment installer et utiliser la bibliothèque cliente pour Spanner, consultez la page Bibliothèques clientes Spanner.


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

public class UpdateUsingDmlWithStructCoreAsyncSample
{
    public async Task<int> UpdateUsingDmlWithStructCoreAsync(string projectId, string instanceId, string databaseId)
    {
        var nameStruct = new SpannerStruct
        {
            { "FirstName", SpannerDbType.String, "Timothy" },
            { "LastName", SpannerDbType.String, "Campbell" }
        };
        string connectionString = $"Data Source=projects/{projectId}/instances/{instanceId}/databases/{databaseId}";

        using var connection = new SpannerConnection(connectionString);
        await connection.OpenAsync();

        using var cmd = connection.CreateDmlCommand("UPDATE Singers SET LastName = 'Grant' WHERE STRUCT<FirstName STRING, LastName STRING>(FirstName, LastName) = @name");
        cmd.Parameters.Add("name", nameStruct.GetSpannerDbType(), nameStruct);
        int rowCount = await cmd.ExecuteNonQueryAsync();

        Console.WriteLine($"{rowCount} row(s) updated...");
        return rowCount;
    }
}

Go

Pour savoir comment installer et utiliser la bibliothèque cliente pour Spanner, consultez la page Bibliothèques clientes Spanner.


import (
	"context"
	"fmt"
	"io"

	"cloud.google.com/go/spanner"
)

func updateUsingDMLStruct(w io.Writer, db string) error {
	ctx := context.Background()
	client, err := spanner.NewClient(ctx, db)
	if err != nil {
		return err
	}
	defer client.Close()

	_, err = client.ReadWriteTransaction(ctx, func(ctx context.Context, txn *spanner.ReadWriteTransaction) error {
		type name struct {
			FirstName string
			LastName  string
		}
		var singerInfo = name{"Timothy", "Campbell"}

		stmt := spanner.Statement{
			SQL: `Update Singers Set LastName = 'Grant'
				WHERE STRUCT<FirstName String, LastName String>(Firstname, LastName) = @name`,
			Params: map[string]interface{}{"name": singerInfo},
		}
		rowCount, err := txn.Update(ctx, stmt)
		if err != nil {
			return err
		}
		fmt.Fprintf(w, "%d record(s) inserted.\n", rowCount)
		return nil
	})
	return err
}

Java

Pour savoir comment installer et utiliser la bibliothèque cliente pour Spanner, consultez la page Bibliothèques clientes Spanner.

static void updateUsingDmlWithStruct(DatabaseClient dbClient) {
  Struct name =
      Struct.newBuilder().set("FirstName").to("Timothy").set("LastName").to("Campbell").build();
  Statement s =
      Statement.newBuilder(
              "UPDATE Singers SET LastName = 'Grant' "
                  + "WHERE STRUCT<FirstName STRING, LastName STRING>(FirstName, LastName) "
                  + "= @name")
          .bind("name")
          .to(name)
          .build();
  dbClient
      .readWriteTransaction()
      .run(transaction -> {
        long rowCount = transaction.executeUpdate(s);
        System.out.printf("%d record updated.\n", rowCount);
        return null;
      });
}

Node.js

Pour savoir comment installer et utiliser la bibliothèque cliente pour Spanner, consultez la page Bibliothèques clientes Spanner.

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

const nameStruct = Spanner.struct({
  FirstName: 'Timothy',
  LastName: 'Campbell',
});

/**
 * 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 instance and database
const instance = spanner.instance(instanceId);
const database = instance.database(databaseId);

database.runTransaction(async (err, transaction) => {
  if (err) {
    console.error(err);
    return;
  }
  try {
    const [rowCount] = await transaction.runUpdate({
      sql: `UPDATE Singers SET LastName = 'Grant'
      WHERE STRUCT<FirstName STRING, LastName STRING>(FirstName, LastName) = @name`,
      params: {
        name: nameStruct,
      },
    });

    console.log(`Successfully updated ${rowCount} record.`);
    await transaction.commit();
  } catch (err) {
    console.error('ERROR:', err);
  } finally {
    // Close the database when finished.
    database.close();
  }
});

PHP

Pour savoir comment installer et utiliser la bibliothèque cliente pour Spanner, consultez la page Bibliothèques clientes Spanner.

use Google\Cloud\Spanner\SpannerClient;
use Google\Cloud\Spanner\Database;
use Google\Cloud\Spanner\Transaction;
use Google\Cloud\Spanner\StructType;
use Google\Cloud\Spanner\StructValue;

/**
 * Update data with a DML statement using Structs.
 *
 * The database and table must already exist and can be created using
 * `create_database`.
 * Example:
 * ```
 * insert_data($instanceId, $databaseId);
 * ```
 *
 * @param string $instanceId The Spanner instance ID.
 * @param string $databaseId The Spanner database ID.
 */
function update_data_with_dml_structs(string $instanceId, string $databaseId): void
{
    $spanner = new SpannerClient();
    $instance = $spanner->instance($instanceId);
    $database = $instance->database($databaseId);

    $database->runTransaction(function (Transaction $t) {
        $nameValue = (new StructValue)
            ->add('FirstName', 'Timothy')
            ->add('LastName', 'Campbell');
        $nameType = (new StructType)
            ->add('FirstName', Database::TYPE_STRING)
            ->add('LastName', Database::TYPE_STRING);

        $rowCount = $t->executeUpdate(
            "UPDATE Singers SET LastName = 'Grant' "
             . 'WHERE STRUCT<FirstName STRING, LastName STRING>(FirstName, LastName) '
             . '= @name',
            [
                'parameters' => [
                    'name' => $nameValue
                ],
                'types' => [
                    'name' => $nameType
                ]
            ]);
        $t->commit();
        printf('Updated %d row(s).' . PHP_EOL, $rowCount);
    });
}

Python

Pour savoir comment installer et utiliser la bibliothèque cliente pour Spanner, consultez la page Bibliothèques clientes Spanner.

# instance_id = "your-spanner-instance"
# database_id = "your-spanner-db-id"

spanner_client = spanner.Client()
instance = spanner_client.instance(instance_id)
database = instance.database(database_id)

record_type = param_types.Struct(
    [
        param_types.StructField("FirstName", param_types.STRING),
        param_types.StructField("LastName", param_types.STRING),
    ]
)
record_value = ("Timothy", "Campbell")

def write_with_struct(transaction):
    row_ct = transaction.execute_update(
        "UPDATE Singers SET LastName = 'Grant' "
        "WHERE STRUCT<FirstName STRING, LastName STRING>"
        "(FirstName, LastName) = @name",
        params={"name": record_value},
        param_types={"name": record_type},
    )
    print("{} record(s) updated.".format(row_ct))

database.run_in_transaction(write_with_struct)

Ruby

Pour savoir comment installer et utiliser la bibliothèque cliente pour Spanner, consultez la page Bibliothèques clientes Spanner.

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

require "google/cloud/spanner"

spanner = Google::Cloud::Spanner.new project: project_id
client  = spanner.client instance_id, database_id
row_count = 0
name_struct = { FirstName: "Timothy", LastName: "Campbell" }

client.transaction do |transaction|
  row_count = transaction.execute_update(
    "UPDATE Singers SET LastName = 'Grant'
     WHERE STRUCT<FirstName STRING, LastName STRING>(FirstName, LastName) = @name",
    params: { name: name_struct }
  )
end

puts "#{row_count} record updated."

Étapes suivantes

Pour rechercher et filtrer des exemples de code pour d'autres produits Google Cloud, consultez l'exemple de navigateur Google Cloud.