Como inserir, atualizar e excluir dados usando a linguagem de manipulação de dados

Nesta página, descrevemos como inserir, atualizar e excluir dados do Cloud Spanner usando declarações de linguagem de manipulação de dados (DML, na sigla em inglês). É possível gerar declarações DML usando as bibliotecas de cliente, o Console do Google Cloud Platform e a ferramenta de linha de comando gcloud. Você também pode executar declarações DML particionadas usando as bibliotecas de cliente e a ferramenta de linha de comando gcloud.

Para ver a referência completa da sintaxe de DML, consulte Sintaxe da linguagem de manipulação de dados.

Como usar a DML

A DML é compatível com declarações INSERT, UPDATE e DELETE no Console do GCP, na ferramenta de linha de comando gcloud e nas bibliotecas de cliente.

Bloqueio

As declarações DML são executadas dentro de transações de leitura e gravação. O Cloud Spanner adquire bloqueios de leitura compartilhados em todas as linhas que ele lê, incluindo linhas que podem não corresponder à condição de filtro da cláusula WHERE. O Cloud Spanner adquire bloqueios exclusivos nas linhas que ele modifica. Como resultado, o Cloud Spanner pode bloquear um grande número de intervalos de linha ou uma tabela inteira, mesmo que a transação modifique apenas algumas das linhas lidas. Para bloquear menos linhas, defina o escopo da cláusula WHERE nas declarações UPDATE e DELETE para pequenos intervalos de chave primária, incluindo as colunas de chave primária na cláusula WHERE.

Simultaneidade

O Cloud Spanner executa sequencialmente todas as instruções SQL (SELECT, INSERT, UPDATE e DELETE) dentro de uma transação. Elas não são executadas simultaneamente. A única exceção é que o Cloud Spanner pode executar várias instruções SELECT simultaneamente, porque elas são operações somente leitura.

Limites de transação

Uma transação que inclui declarações DML tem os mesmos limites que qualquer outra transação. Se você tiver alterações em grande escala, considere o uso de DML particionada.

  • Se as declarações DML em uma transação resultarem em mais de 20.000 mutações, a declaração DML que faz com que a transação ultrapasse o limite retorna um erro BadUsage com uma mensagem sobre muitas mutações.

  • Se as declarações DML em uma transação resultarem em uma transação maior que 100 MB, a declaração DML que faz com que a transação ultrapasse o limite retorna um erro BadUsage com uma mensagem sobre o limite de tamanho excedido.

Mutações realizadas usando DML não são retornadas ao cliente. Elas são mescladas na solicitação de confirmação quando ela é confirmada e contam para os limites de tamanho máximo. Mesmo que o tamanho da solicitação de confirmação enviada seja pequeno, a transação ainda poderá exceder o limite de tamanho permitido.

Executar declarações no Console do GCP

Use as etapas a seguir para executar uma declaração DML no Console do GCP.

  1. Acesse a página Instâncias do Cloud Spanner.

    Acessar a página "Instâncias"

  2. Selecione o projeto na lista suspensa na barra de ferramentas.

  3. Clique no nome da instância que contém seu banco de dados para ir para a página Detalhes da instância.

  4. Na guia Visão geral, clique no nome do seu banco de dados. A página Detalhes do banco de dados é exibida.

  5. Clique em Consulta.

  6. Digite uma declaração DML. Por exemplo, a declaração a seguir adiciona uma nova linha à tabela Singers.

    INSERT Singers (SingerId, FirstName, LastName)
    VALUES (1, 'Marc', 'Richards')
    
  7. Clique em Executar consulta. O Console do GCP exibe o resultado.

Executar instruções com a ferramenta de linha de comando gcloud

Para executar declarações DML, use o comando gcloud spanner databases execute-sql. O exemplo a seguir adiciona uma nova linha à tabela Singers.

gcloud spanner databases execute-sql example-db --instance=test-instance \
    --sql="INSERT Singers (SingerId, FirstName, LastName) VALUES (1, 'Marc', 'Richards')"

Modificar dados usando a biblioteca de cliente

Para executar declarações DML com a biblioteca de cliente:

  • Crie uma transação de leitura/gravação.
  • Chame o método da biblioteca de cliente para a execução da DML e transmita a declaração DML.
  • Use o valor de retorno do método de execução da DML para receber o número de linhas inseridas, atualizadas ou excluídas.

O exemplo de código a seguir insere uma nova linha na tabela Singers.

C#

Use o método ExecuteNonQueryAsync() para executar uma declaração DML.

public static async Task InsertUsingDmlCoreAsync(
    string projectId,
    string instanceId,
    string databaseId)
{
    string connectionString =
        $"Data Source=projects/{projectId}/instances/{instanceId}"
        + $"/databases/{databaseId}";

    // Create connection to Cloud Spanner.
    using (var connection =
        new SpannerConnection(connectionString))
    {
        await connection.OpenAsync();

        SpannerCommand cmd = connection.CreateDmlCommand(
           "INSERT Singers (SingerId, FirstName, LastName) "
           + "VALUES (10, 'Virginia', 'Watson')");
        int rowCount = await cmd.ExecuteNonQueryAsync();
        Console.WriteLine($"{rowCount} row(s) inserted...");
    }
}

Go

Use o método Update() para executar uma declaração DML.

func insertUsingDML(ctx context.Context, w io.Writer, client *spanner.Client) error {
	_, err := client.ReadWriteTransaction(ctx, func(ctx context.Context, txn *spanner.ReadWriteTransaction) error {
		stmt := spanner.Statement{
			SQL: `INSERT Singers (SingerId, FirstName, LastName)
					VALUES (10, 'Virginia', 'Watson')`,
		}
		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

Use o método executeUpdate() para executar uma declaração DML.

static void insertUsingDml(DatabaseClient dbClient) {
  dbClient
      .readWriteTransaction()
      .run(
          new TransactionCallable<Void>() {
            @Override
            public Void run(TransactionContext transaction) throws Exception {
              String sql =
                  "INSERT INTO Singers (SingerId, FirstName, LastName) "
                      + " VALUES (10, 'Virginia', 'Watson')";
              long rowCount = transaction.executeUpdate(Statement.of(sql));
              System.out.printf("%d record inserted.\n", rowCount);
              return null;
            }
          });
}

Node.js

Use o método runUpdate() para executar uma declaração DML.

// 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 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:
        'INSERT Singers (SingerId, FirstName, LastName) VALUES (10, @firstName, @lastName)',
      params: {
        firstName: 'Virginia',
        lastName: 'Watson',
      },
    });

    console.log(
      `Successfully inserted ${rowCount} record into the Singers table.`
    );

    await transaction.commit();
  } catch (err) {
    console.error('ERROR:', err);
  } finally {
    // Close the database when finished.
    database.close();
  }
});

PHP

Use o método executeUpdate() para executar uma declaração DML.

use Google\Cloud\Spanner\SpannerClient;
use Google\Cloud\Spanner\Transaction;

/**
 * Inserts sample data into the given database with a DML statement.
 *
 * 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 $databaseId The Spanner database ID.
 */
function insert_data_with_dml($instanceId, $databaseId)
{
    $spanner = new SpannerClient();
    $instance = $spanner->instance($instanceId);
    $database = $instance->database($databaseId);

    $database->runTransaction(function (Transaction $t) use ($spanner) {
        $rowCount = $t->executeUpdate(
            "INSERT Singers (SingerId, FirstName, LastName) "
            . " VALUES (10, 'Virginia', 'Watson')");
        $t->commit();
        printf('Inserted %d row(s).' . PHP_EOL, $rowCount);
    });
}

Python

Use o método execute_update() para executar uma declaração DML.

# 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)

def insert_singers(transaction):
    row_ct = transaction.execute_update(
        "INSERT Singers (SingerId, FirstName, LastName) "
        " VALUES (10, 'Virginia', 'Watson')"
    )

    print("{} record(s) inserted.".format(row_ct))

database.run_in_transaction(insert_singers)

Ruby

Use o método execute_update() para executar uma declaração DML.

# 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

client.transaction do |transaction|
  row_count = transaction.execute_update(
    "INSERT INTO Singers (SingerId, FirstName, LastName) VALUES (10, 'Virginia', 'Watson')"
  )
end

puts "#{row_count} record inserted."

O exemplo de código a seguir atualiza a coluna MarketingBudget da tabela Albums com base em uma cláusula WHERE.

C#

public static async Task UpdateUsingDmlCoreAsync(
    string projectId,
    string instanceId,
    string databaseId)
{
    string connectionString =
        $"Data Source=projects/{projectId}/instances/{instanceId}"
        + $"/databases/{databaseId}";

    // Create connection to Cloud Spanner.
    using (var connection =
        new SpannerConnection(connectionString))
    {
        await connection.OpenAsync();

        SpannerCommand cmd = connection.CreateDmlCommand(
           "UPDATE Albums SET MarketingBudget = MarketingBudget * 2 "
           + "WHERE SingerId = 1 and AlbumId = 1");
        int rowCount = await cmd.ExecuteNonQueryAsync();
        Console.WriteLine($"{rowCount} row(s) updated...");
    }
}

Go

func updateUsingDML(ctx context.Context, w io.Writer, client *spanner.Client) error {
	_, err := client.ReadWriteTransaction(ctx, func(ctx context.Context, txn *spanner.ReadWriteTransaction) error {
		stmt := spanner.Statement{
			SQL: `UPDATE Albums
				SET MarketingBudget = MarketingBudget * 2
				WHERE SingerId = 1 and AlbumId = 1`,
		}
		rowCount, err := txn.Update(ctx, stmt)
		if err != nil {
			return err
		}
		fmt.Fprintf(w, "%d record(s) updated.\n", rowCount)
		return nil
	})
	return err
}

Java

static void updateUsingDml(DatabaseClient dbClient) {
  dbClient
      .readWriteTransaction()
      .run(
          new TransactionCallable<Void>() {
            @Override
            public Void run(TransactionContext transaction) throws Exception {
              String sql =
                  "UPDATE Albums "
                      + "SET MarketingBudget = MarketingBudget * 2 "
                      + "WHERE SingerId = 1 and AlbumId = 1";
              long rowCount = transaction.executeUpdate(Statement.of(sql));
              System.out.printf("%d record updated.\n", rowCount);
              return null;
            }
          });
}

Node.js

// 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 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 Albums SET MarketingBudget = MarketingBudget * 2
        WHERE SingerId = 1 and AlbumId = 1`,
    });

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

PHP

use Google\Cloud\Spanner\SpannerClient;
use Google\Cloud\Spanner\Transaction;

/**
 * Updates sample data in the database with a DML statement.
 *
 * This requires the `MarketingBudget` column which must be created before
 * running this sample. You can add the column by running the `add_column`
 * sample or by running this DDL statement against your database:
 *
 *     ALTER TABLE Albums ADD COLUMN MarketingBudget INT64
 *
 * Example:
 * ```
 * update_data($instanceId, $databaseId);
 * ```
 *
 * @param string $instanceId The Spanner instance ID.
 * @param string $databaseId The Spanner database ID.
 */
function update_data_with_dml($instanceId, $databaseId)
{
    $spanner = new SpannerClient();
    $instance = $spanner->instance($instanceId);
    $database = $instance->database($databaseId);

    $database->runTransaction(function (Transaction $t) use ($spanner) {
        $rowCount = $t->executeUpdate(
            "UPDATE Albums "
            . "SET MarketingBudget = MarketingBudget * 2 "
            . "WHERE SingerId = 1 and AlbumId = 1");
        $t->commit();
        printf('Updated %d row(s).' . PHP_EOL, $rowCount);
    });
}

Python

# 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)

def update_albums(transaction):
    row_ct = transaction.execute_update(
        "UPDATE Albums "
        "SET MarketingBudget = MarketingBudget * 2 "
        "WHERE SingerId = 1 and AlbumId = 1"
    )

    print("{} record(s) updated.".format(row_ct))

database.run_in_transaction(update_albums)

Ruby

# 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

client.transaction do |transaction|
  row_count = transaction.execute_update(
    "UPDATE Albums
     SET MarketingBudget = MarketingBudget * 2
     WHERE SingerId = 1 and AlbumId = 1"
  )
end

puts "#{row_count} record updated."

O exemplo de código a seguir exclui todas as linhas da tabela Singers que têm o valor Alice na coluna FirstName.

C#

public static async Task DeleteUsingDmlCoreAsync(
    string projectId,
    string instanceId,
    string databaseId)
{
    string connectionString =
        $"Data Source=projects/{projectId}/instances/{instanceId}"
        + $"/databases/{databaseId}";

    // Create connection to Cloud Spanner.
    using (var connection =
        new SpannerConnection(connectionString))
    {
        await connection.OpenAsync();

        SpannerCommand cmd = connection.CreateDmlCommand(
           "DELETE Singers WHERE FirstName = 'Alice'");
        int rowCount = await cmd.ExecuteNonQueryAsync();
        Console.WriteLine($"{rowCount} row(s) deleted...");
    }
}

Go

func deleteUsingDML(ctx context.Context, w io.Writer, client *spanner.Client) error {
	_, err := client.ReadWriteTransaction(ctx, func(ctx context.Context, txn *spanner.ReadWriteTransaction) error {
		stmt := spanner.Statement{SQL: `DELETE Singers WHERE FirstName = 'Alice'`}
		rowCount, err := txn.Update(ctx, stmt)
		if err != nil {
			return err
		}
		fmt.Fprintf(w, "%d record(s) deleted.\n", rowCount)
		return nil
	})
	return err
}

Java

static void deleteUsingDml(DatabaseClient dbClient) {
  dbClient
      .readWriteTransaction()
      .run(
          new TransactionCallable<Void>() {
            @Override
            public Void run(TransactionContext transaction) throws Exception {
              String sql = "DELETE FROM Singers WHERE FirstName = 'Alice'";
              long rowCount = transaction.executeUpdate(Statement.of(sql));
              System.out.printf("%d record deleted.\n", rowCount);
              return null;
            }
          });
}

Node.js

// 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 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: `DELETE Singers WHERE FirstName = 'Alice'`,
    });

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

PHP

use Google\Cloud\Spanner\SpannerClient;
use Google\Cloud\Spanner\Transaction;

/**
 * Deletes sample data in the database with a DML statement.
 *
 * @param string $instanceId The Spanner instance ID.
 * @param string $databaseId The Spanner database ID.
 */
function delete_data_with_dml($instanceId, $databaseId)
{
    $spanner = new SpannerClient();
    $instance = $spanner->instance($instanceId);
    $database = $instance->database($databaseId);

    $database->runTransaction(function (Transaction $t) use ($spanner) {
        $rowCount = $t->executeUpdate(
            "DELETE Singers WHERE FirstName = 'Alice'");
        $t->commit();
        printf('Deleted %d row(s).' . PHP_EOL, $rowCount);
    });
}

Python

# 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)

def delete_singers(transaction):
    row_ct = transaction.execute_update(
        "DELETE Singers WHERE FirstName = 'Alice'"
    )

    print("{} record(s) deleted.".format(row_ct))

database.run_in_transaction(delete_singers)

Ruby

# 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

client.transaction do |transaction|
  row_count = transaction.execute_update(
    "DELETE FROM Singers WHERE FirstName = 'Alice'"
  )
end

puts "#{row_count} record deleted."

O exemplo a seguir usa um STRUCT com parâmetros associados para atualizar o LastName nas linhas filtradas por FirstName e LastName.

C#

public static async Task 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}";

    // Create connection to Cloud Spanner.
    using (var connection =
        new SpannerConnection(connectionString))
    {
        await connection.OpenAsync();

        SpannerCommand 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...");
    }
}

Go

func updateUsingDMLStruct(ctx context.Context, w io.Writer, client *spanner.Client) error {
	_, 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

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(
          new TransactionCallable<Void>() {
            @Override
            public Void run(TransactionContext transaction) throws Exception {
              long rowCount = transaction.executeUpdate(s);
              System.out.printf("%d record updated.\n", rowCount);
              return null;
            }
          });
}

Node.js

// 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

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 $databaseId The Spanner database ID.
 */
function update_data_with_dml_structs($instanceId, $databaseId)
{
    $spanner = new SpannerClient();
    $instance = $spanner->instance($instanceId);
    $database = $instance->database($databaseId);

    $database->runTransaction(function (Transaction $t) use ($spanner) {
        $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

# 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

# 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."

Ler dados gravados na mesma transação

As alterações que você faz usando declarações DML são visíveis para declarações subsequentes na mesma transação. Isso é diferente de usar mutações, em que as alterações não são visíveis até que a transação seja confirmada.

Cloud Spanner verifica as restrições após cada declaração DML. Isso é diferente de usar mutações, em que o Cloud Spanner armazena mutações no cliente até confirmar e verificar as restrições no momento do commit. A avaliação das restrições após cada declaração permite que o Cloud Spanner garanta que os dados que uma declaração DML retorna são consistentes com o esquema.

O exemplo a seguir atualiza uma linha na tabela Singers e executa uma declaração SELECT para exibir os novos valores.

C#

public static async Task WriteAndReadUsingDmlCoreAsync(
    string projectId,
    string instanceId,
    string databaseId)
{
    string connectionString =
        $"Data Source=projects/{projectId}/instances/{instanceId}"
        + $"/databases/{databaseId}";

    // Create connection to Cloud Spanner.
    using (var connection =
        new SpannerConnection(connectionString))
    {
        await connection.OpenAsync();

        SpannerCommand cmd = connection.CreateDmlCommand(
           @"INSERT Singers (SingerId, FirstName, LastName)
              VALUES (11, 'Timothy', 'Campbell')");
        int rowCount = await cmd.ExecuteNonQueryAsync();
        Console.WriteLine($"{rowCount} row(s) inserted...");
        // Read newly inserted record.
        cmd = connection.CreateSelectCommand(
            @"SELECT FirstName, LastName FROM Singers
              WHERE SingerId = 11");
        using (var reader = await cmd.ExecuteReaderAsync())
        {
            while (await reader.ReadAsync())
            {
                Console.WriteLine(
                    reader.GetFieldValue<string>("FirstName") + " "
                    + reader.GetFieldValue<string>("LastName"));
            }
        }
    }
}

Go

func writeAndReadUsingDML(ctx context.Context, w io.Writer, client *spanner.Client) error {
	_, err := client.ReadWriteTransaction(ctx, func(ctx context.Context, txn *spanner.ReadWriteTransaction) error {
		// Insert Record
		stmt := spanner.Statement{
			SQL: `INSERT Singers (SingerId, FirstName, LastName)
				VALUES (11, 'Timothy', 'Campbell')`,
		}
		rowCount, err := txn.Update(ctx, stmt)
		if err != nil {
			return err
		}
		fmt.Fprintf(w, "%d record(s) inserted.\n", rowCount)

		// Read newly inserted record
		stmt = spanner.Statement{SQL: `SELECT FirstName, LastName FROM Singers WHERE SingerId = 11`}
		iter := txn.Query(ctx, stmt)
		defer iter.Stop()

		for {
			row, err := iter.Next()
			if err == iterator.Done || err != nil {
				break
			}
			var firstName, lastName string
			if err := row.ColumnByName("FirstName", &firstName); err != nil {
				return err
			}
			if err := row.ColumnByName("LastName", &lastName); err != nil {
				return err
			}
			fmt.Fprintf(w, "Found record name with %s, %s", firstName, lastName)
		}
		return err
	})
	return err
}

Java

static void writeAndReadUsingDml(DatabaseClient dbClient) {
  dbClient
      .readWriteTransaction()
      .run(
          new TransactionCallable<Void>() {
            @Override
            public Void run(TransactionContext transaction) throws Exception {
              // Insert record.
              String sql =
                  "INSERT INTO Singers (SingerId, FirstName, LastName) "
                      + " VALUES (11, 'Timothy', 'Campbell')";
              long rowCount = transaction.executeUpdate(Statement.of(sql));
              System.out.printf("%d record inserted.\n", rowCount);
              // Read newly inserted record.
              sql = "SELECT FirstName, LastName FROM Singers WHERE SingerId = 11";
              ResultSet resultSet = transaction.executeQuery(Statement.of(sql));
              while (resultSet.next()) {
                System.out.printf(
                    "%s %s\n", resultSet.getString("FirstName"), resultSet.getString("LastName"));
              }
              return null;
            }
          });
}

Node.js

// 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 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 {
    await transaction.runUpdate({
      sql: `INSERT Singers (SingerId, FirstName, LastName)
        VALUES (11, 'Timothy', 'Campbell')`,
    });

    const [rows] = await transaction.run({
      sql: `SELECT FirstName, LastName FROM Singers`,
    });
    rows.forEach(row => {
      const json = row.toJSON();
      console.log(`${json.FirstName} ${json.LastName}`);
    });

    await transaction.commit();
  } catch (err) {
    console.error('ERROR:', err);
  } finally {
    // Close the database when finished.
    database.close();
  }
});

PHP

use Google\Cloud\Spanner\SpannerClient;
use Google\Cloud\Spanner\Transaction;

/**
 * Writes then reads data inside a Transaction with a DML statement.
 *
 * 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 $databaseId The Spanner database ID.
 */
function write_read_with_dml($instanceId, $databaseId)
{
    $spanner = new SpannerClient();
    $instance = $spanner->instance($instanceId);
    $database = $instance->database($databaseId);

    $database->runTransaction(function (Transaction $t) use ($spanner) {
        $rowCount = $t->executeUpdate(
            "INSERT Singers (SingerId, FirstName, LastName) "
            . " VALUES (11, 'Timothy', 'Campbell')");

        printf('Inserted %d row(s).' . PHP_EOL, $rowCount);

        $results = $t->execute("SELECT FirstName, LastName FROM Singers WHERE SingerId = 11");

        foreach ($results as $row) {
            printf('%s %s' . PHP_EOL, $row['FirstName'], $row['LastName']);
        }

        $t->commit();
    });
}

Python

# 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)

def write_then_read(transaction):
    # Insert record.
    row_ct = transaction.execute_update(
        "INSERT Singers (SingerId, FirstName, LastName) "
        " VALUES (11, 'Timothy', 'Campbell')"
    )
    print("{} record(s) inserted.".format(row_ct))

    # Read newly inserted record.
    results = transaction.execute_sql(
        "SELECT FirstName, LastName FROM Singers WHERE SingerId = 11"
    )
    for result in results:
        print("FirstName: {}, LastName: {}".format(*result))

database.run_in_transaction(write_then_read)

Ruby

# 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

client.transaction do |transaction|
  row_count = transaction.execute_update(
    "INSERT INTO Singers (SingerId, FirstName, LastName) VALUES (11, 'Timothy', 'Campbell')"
  )
  puts "#{row_count} record updated."
  transaction.execute("SELECT FirstName, LastName FROM Singers WHERE SingerId = 11").rows.each do |row|
    puts "#{row[:FirstName]} #{row[:LastName]}"
  end
end

Gravar carimbos de data/hora de commit

Use a função PENDING_COMMIT_TIMESTAMP para gravar o carimbo de data/hora de confirmação em uma declaração DML. O Cloud Spanner seleciona o carimbo de data/hora de commit quando a transação é confirmada.

O exemplo de código a seguir usa a função PENDING_COMMIT_TIMESTAMP para gravar o carimbo de data/hora de confirmação na coluna LastUpdateTime.

C#

public static async Task UpdateUsingDmlWithTimestampCoreAsync(
    string projectId,
    string instanceId,
    string databaseId)
{
    string connectionString =
        $"Data Source=projects/{projectId}/instances/{instanceId}"
        + $"/databases/{databaseId}";

    // Create connection to Cloud Spanner.
    using (var connection =
        new SpannerConnection(connectionString))
    {
        await connection.OpenAsync();

        SpannerCommand cmd = connection.CreateDmlCommand(
           "UPDATE Albums "
           + "SET LastUpdateTime = PENDING_COMMIT_TIMESTAMP() "
           + "WHERE SingerId = 1");
        int rowCount = await cmd.ExecuteNonQueryAsync();
        Console.WriteLine($"{rowCount} row(s) updated...");
    }
}

Go

func updateUsingDMLWithTimestamp(ctx context.Context, w io.Writer, client *spanner.Client) error {
	_, err := client.ReadWriteTransaction(ctx, func(ctx context.Context, txn *spanner.ReadWriteTransaction) error {
		stmt := spanner.Statement{
			SQL: `UPDATE Albums
				SET LastUpdateTime = PENDING_COMMIT_TIMESTAMP()
				WHERE SingerId = 1`,
		}
		rowCount, err := txn.Update(ctx, stmt)
		if err != nil {
			return err
		}
		fmt.Fprintf(w, "%d record(s) updated.\n", rowCount)
		return nil
	})
	return err
}

Java

static void updateUsingDmlWithTimestamp(DatabaseClient dbClient) {
  dbClient
      .readWriteTransaction()
      .run(
          new TransactionCallable<Void>() {
            @Override
            public Void run(TransactionContext transaction) throws Exception {
              String sql =
                  "UPDATE Albums "
                      + "SET LastUpdateTime = PENDING_COMMIT_TIMESTAMP() WHERE SingerId = 1";
              long rowCount = transaction.executeUpdate(Statement.of(sql));
              System.out.printf("%d records updated.\n", rowCount);
              return null;
            }
          });
}

Node.js

// 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 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 Albums
        SET LastUpdateTime = PENDING_COMMIT_TIMESTAMP()
        WHERE SingerId = 1`,
    });

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

PHP

use Google\Cloud\Spanner\SpannerClient;
use Google\Cloud\Spanner\Transaction;

/**
 * Update data with a DML statement using timestamps.
 *
 * 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 $databaseId The Spanner database ID.
 */
function update_data_with_dml_timestamp($instanceId, $databaseId)
{
    $spanner = new SpannerClient();
    $instance = $spanner->instance($instanceId);
    $database = $instance->database($databaseId);

    $database->runTransaction(function (Transaction $t) use ($spanner) {
        $rowCount = $t->executeUpdate(
            "UPDATE Albums "
            . "SET LastUpdateTime = PENDING_COMMIT_TIMESTAMP() WHERE SingerId = 1");
        $t->commit();
        printf('Updated %d row(s).' . PHP_EOL, $rowCount);
    });
}

Python

# 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)

def update_albums(transaction):
    row_ct = transaction.execute_update(
        "UPDATE Albums "
        "SET LastUpdateTime = PENDING_COMMIT_TIMESTAMP() "
        "WHERE SingerId = 1"
    )

    print("{} record(s) updated.".format(row_ct))

database.run_in_transaction(update_albums)

Ruby

# 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

client.transaction do |transaction|
  row_count = transaction.execute_update(
    "UPDATE Albums SET LastUpdateTime = PENDING_COMMIT_TIMESTAMP() WHERE SingerId = 1"
  )
end

puts "#{row_count} records updated."

Receber o plano de consulta

É possível recuperar um plano de consulta usando o Console do GCP, as bibliotecas de cliente e a ferramenta de linha de comando gcloud.

Usar a DML particionada

A DML particionada foi projetada para atualizações e exclusões em massa, particularmente limpeza periódica e preenchimento.

Executar instruções com a ferramenta de linha de comando gcloud

Para executar uma declaração DML particionada, use o comando gcloud spanner databases execute-sql com a opção --enable-partitioned-dml. O exemplo a seguir atualiza linhas na tabela Albums.

gcloud spanner databases execute-sql example-db \
    --instance=test-instance --enable-partitioned-dml \
    --sql='UPDATE Albums SET MarketingBudget = 0 WHERE MarketingBudget IS NULL'

Modificar dados usando a biblioteca de cliente

O exemplo de código a seguir atualiza a coluna MarketingBudget da tabela Albums.

C#

Use o método ExecutePartitionedUpdateAsync() para executar uma declaração DML particionada.

public static async Task UpdateUsingPartitionedDmlCoreAsync(
    string projectId,
    string instanceId,
    string databaseId)
{
    string connectionString =
        $"Data Source=projects/{projectId}/instances/{instanceId}"
        + $"/databases/{databaseId}";

    // Create connection to Cloud Spanner.
    using (var connection =
        new SpannerConnection(connectionString))
    {
        await connection.OpenAsync();

        SpannerCommand cmd = connection.CreateDmlCommand(
            "UPDATE Albums SET MarketingBudget = 100000 WHERE SingerId > 1"
        );
        long rowCount = await cmd.ExecutePartitionedUpdateAsync();
        Console.WriteLine($"{rowCount} row(s) updated...");
    }
}

Go

Use o método PartitionedUpdate() para executar uma declaração DML particionada.

func updateUsingPartitionedDML(ctx context.Context, w io.Writer, client *spanner.Client) error {
	stmt := spanner.Statement{SQL: "UPDATE Albums SET MarketingBudget = 100000 WHERE SingerId > 1"}
	rowCount, err := client.PartitionedUpdate(ctx, stmt)
	if err != nil {
		return err
	}
	fmt.Fprintf(w, "%d record(s) updated.\n", rowCount)
	return nil
}

Java

Use o método executePartitionedUpdate() para executar uma declaração DML particionada.

static void updateUsingPartitionedDml(DatabaseClient dbClient) {
  String sql = "UPDATE Albums SET MarketingBudget = 100000 WHERE SingerId > 1";
  long rowCount = dbClient.executePartitionedUpdate(Statement.of(sql));
  System.out.printf("%d records updated.\n", rowCount);
}

Node.js

Use o método runPartitionedUpdate() para executar uma declaração DML particionada.

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

try {
  const [rowCount] = await database.runPartitionedUpdate({
    sql: `UPDATE Albums SET MarketingBudget = 100000 WHERE SingerId > 1`,
  });
  console.log(`Successfully updated ${rowCount} records.`);
} catch (err) {
  console.error('ERROR:', err);
} finally {
  // Close the database when finished.
  database.close();
}

PHP

Use o método executePartitionedUpdate() para executar uma declaração DML particionada.

use Google\Cloud\Spanner\SpannerClient;

/**
 * Updates sample data in the database by partition with a DML statement.
 *
 * This updates the `MarketingBudget` column which must be created before
 * running this sample. You can add the column by running the `add_column`
 * sample or by running this DDL statement against your database:
 *
 *     ALTER TABLE Albums ADD COLUMN MarketingBudget INT64
 *
 * Example:
 * ```
 * update_data($instanceId, $databaseId);
 * ```
 *
 * @param string $instanceId The Spanner instance ID.
 * @param string $databaseId The Spanner database ID.
 */
function update_data_with_partitioned_dml($instanceId, $databaseId)
{
    $spanner = new SpannerClient();
    $instance = $spanner->instance($instanceId);
    $database = $instance->database($databaseId);

    $rowCount = $database->executePartitionedUpdate(
        "UPDATE Albums SET MarketingBudget = 100000 WHERE SingerId > 1"
    );

    printf('Updated %d row(s).' . PHP_EOL, $rowCount);
}

Python

Use o método execute_partitioned_dml() para executar uma declaração DML particionada.

# 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)

row_ct = database.execute_partitioned_dml(
    "UPDATE Albums SET MarketingBudget = 100000 WHERE SingerId > 1"
)

print("{} records updated.".format(row_ct))

Ruby

Use o método execute_partitioned_update() para executar uma declaração DML particionada.

# 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 = client.execute_partition_update(
  "UPDATE Albums SET MarketingBudget = 100000 WHERE SingerId > 1"
)

puts "#{row_count} records updated."

O exemplo de código a seguir exclui linhas da tabela Singers, com base na coluna SingerId.

C#

public static async Task DeleteUsingPartitionedDmlCoreAsync(
    string projectId,
    string instanceId,
    string databaseId)
{
    string connectionString =
        $"Data Source=projects/{projectId}/instances/{instanceId}"
        + $"/databases/{databaseId}";

    // Create connection to Cloud Spanner.
    using (var connection =
        new SpannerConnection(connectionString))
    {
        await connection.OpenAsync();

        SpannerCommand cmd = connection.CreateDmlCommand(
            "DELETE Singers WHERE SingerId > 10"
        );
        long rowCount = await cmd.ExecutePartitionedUpdateAsync();
        Console.WriteLine($"{rowCount} row(s) deleted...");
    }
}

Go

func deleteUsingPartitionedDML(ctx context.Context, w io.Writer, client *spanner.Client) error {
	stmt := spanner.Statement{SQL: "DELETE Singers WHERE SingerId > 10"}
	rowCount, err := client.PartitionedUpdate(ctx, stmt)
	if err != nil {
		return err

	}
	fmt.Fprintf(w, "%d record(s) deleted.", rowCount)
	return nil
}

Java

static void deleteUsingPartitionedDml(DatabaseClient dbClient) {
  String sql = "DELETE FROM Singers WHERE SingerId > 10";
  long rowCount = dbClient.executePartitionedUpdate(Statement.of(sql));
  System.out.printf("%d records deleted.\n", rowCount);
}

Node.js

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

try {
  const [rowCount] = await database.runPartitionedUpdate({
    sql: `DELETE Singers WHERE SingerId > 10`,
  });
  console.log(`Successfully deleted ${rowCount} records.`);
} catch (err) {
  console.error('ERROR:', err);
} finally {
  // Close the database when finished.
  database.close();
}

PHP

use Google\Cloud\Spanner\SpannerClient;

/**
 * Delete sample data in the database by partition with a DML statement.
 *
 * This updates the `MarketingBudget` column which must be created before
 * running this sample. You can add the column by running the `add_column`
 * sample or by running this DDL statement against your database:
 *
 *     ALTER TABLE Albums ADD COLUMN MarketingBudget INT64
 *
 * Example:
 * ```
 * update_data($instanceId, $databaseId);
 * ```
 *
 * @param string $instanceId The Spanner instance ID.
 * @param string $databaseId The Spanner database ID.
 */
function delete_data_with_partitioned_dml($instanceId, $databaseId)
{
    $spanner = new SpannerClient();
    $instance = $spanner->instance($instanceId);
    $database = $instance->database($databaseId);

    $rowCount = $database->executePartitionedUpdate(
        "DELETE Singers WHERE SingerId > 10"
    );

    printf('Deleted %d row(s).' . PHP_EOL, $rowCount);
}

Python

# 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)

row_ct = database.execute_partitioned_dml(
    "DELETE Singers WHERE SingerId > 10"
)

print("{} record(s) deleted.".format(row_ct))

Ruby

# 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 = client.execute_partition_update(
  "DELETE FROM Singers WHERE SingerId > 10"
)

puts "#{row_count} records deleted."
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