En esta página, se describe cómo insertar, actualizar y borrar datos de Spanner mediante declaraciones de lenguaje de manipulación de datos (DML). Puedes ejecutar declaraciones DML mediante las bibliotecas cliente, la consola de Google Cloud y la herramienta de línea de comandos de gcloud. Puedes ejecutar declaraciones de DML particionadas mediante las bibliotecas cliente y la herramienta de línea de comandos de gcloud.
Si deseas obtener la referencia completa de la sintaxis del DML, consulta Sintaxis del lenguaje de manipulación de datos para las bases de datos con dialectos de GoogleSQL o el lenguaje de manipulación de datos de PostgreSQL para las bases de datos con dialectos de PostgreSQL.
Usar DML
El DML admite declaraciones INSERT, UPDATE y DELETE en la
consola de Google Cloud, Google Cloud CLI y las bibliotecas cliente.
Bloqueo
Las declaraciones DML se pueden ejecutar dentro de transacciones de lectura y escritura. Cuando Spanner lee datos, adquiere bloqueos de lectura compartidos en partes limitadas de los rangos de filas que lees. En particular, adquiere estos bloqueos solo en las columnas a las que accedes. Los bloqueos pueden incluir datos que no cumplan con la condición del filtro de la cláusula WHERE.
Cuando Spanner modifica datos mediante declaraciones DML, adquiere bloqueos exclusivos en los datos específicos que estás modificando. Además, adquiere bloqueos compartidos de la misma manera que cuando lees datos. Si tu solicitud incluye grandes rangos de filas o una tabla completa, es posible que los bloqueos compartidos impidan que otras transacciones progresen en paralelo.
Para modificar los datos de la manera más eficiente posible, usa una cláusula WHERE que permita que Spanner lea solo las filas necesarias. Puedes lograr este objetivo con un filtro en la clave primaria o en la clave de un índice secundario. La cláusula WHERE limita el alcance de los bloqueos compartidos y permite que Spanner procese la actualización de manera más eficiente.
Por ejemplo, supongamos que uno de los músicos de la tabla Singers cambia su nombre y tienes que actualizarlo en tu base de datos. Podrías ejecutar la siguiente declaración DML, pero obliga a Spanner a analizar toda la tabla y adquiere bloqueos compartidos que
cubren toda la tabla. Como resultado, Spanner debe leer más datos de los necesarios, y las transacciones simultáneas no pueden modificar los datos en paralelo:
-- ANTI-PATTERN: SENDING AN UPDATE WITHOUT THE PRIMARY KEY COLUMN
-- IN THE WHERE CLAUSE
UPDATE Singers SET FirstName = "Marcel"
WHERE FirstName = "Marc" AND LastName = "Richards";
Para que la actualización sea más eficiente, incluye la columna SingerId en la cláusula WHERE. La columna SingerId es la única columna de clave primaria de la tabla Singers:
-- ANTI-PATTERN: SENDING AN UPDATE THAT MUST SCAN THE ENTIRE TABLE
UPDATE Singers SET FirstName = "Marcel"
WHERE FirstName = "Marc" AND LastName = "Richards"
Si no hay un índice en FirstName o LastName, debes analizar toda la tabla para encontrar los cantantes objetivo. Si no quieres agregar un índice secundario para que la actualización sea más eficiente, incluye la columna SingerId en la cláusula WHERE.
La columna SingerId es la única columna de clave primaria de la tabla Singers. Para encontrarla, ejecuta SELECT en una transacción independiente de solo lectura antes de la transacción de actualización:
SELECT SingerId
FROM Singers
WHERE FirstName = "Marc" AND LastName = "Richards"
-- Recommended: Including a seekable filter in the where clause
UPDATE Singers SET FirstName = "Marcel"
WHERE SingerId = 1;
Simultaneidad
Spanner ejecuta de forma secuencial todas las instrucciones de SQL (SELECT,
INSERT, UPDATE y DELETE) dentro de una transacción. No se ejecutan al mismo tiempo. La única excepción es que Spanner podría ejecutar varias declaraciones SELECT de forma simultánea, ya que son operaciones de solo lectura.
Límites de transacciones
Una transacción que incluye declaraciones DML tiene los mismos límites que cualquier otra transacción. Si tienes que realizar cambios a gran escala, considera usar DML particionado.
Si las declaraciones DML de una transacción generan más de 80,000 mutaciones, la declaración DML que envía la transacción por encima del límite muestra un error
BadUsagecon un mensaje que indica que hay demasiadas mutaciones.Si las declaraciones DML de una transacción generan una transacción superior a 100 MB, la declaración DML que envía la transacción por encima del límite muestra un error
BadUsagecon un mensaje de que la transacción supera el límite de tamaño.
Las mutaciones que se realizan con DML no se muestran al cliente. Se combinan en la solicitud de confirmación cuando se confirma y cuentan para los límites de tamaño máximo. Incluso si el tamaño de la solicitud de confirmación que envías es pequeño, la transacción podría superar el límite de tamaño permitido.
Ejecuta sentencias en la consola de Google Cloud
Usa los siguientes pasos para ejecutar una declaración DML en la consola de Google Cloud.
Ve a la página Instancias de Spanner.
Selecciona tu proyecto en la lista desplegable de la barra de herramientas.
Haz clic en el nombre de la instancia que contiene tu base de datos para ir a la página Detalles de la instancia.
En la pestaña Descripción general, haz clic en el nombre de tu base de datos. Aparecerá la página Detalles de la base de datos.
Haz clic en Spanner Studio.
Ingresa una declaración DML. Por ejemplo, con la declaración siguiente, se agrega una fila nueva a la tabla
Singers.INSERT Singers (SingerId, FirstName, LastName) VALUES (1, 'Marc', 'Richards')Haz clic en Ejecutar consulta. La consola de Google Cloud muestra el resultado.
Ejecuta sentencias con Google Cloud CLI
Para ejecutar declaraciones DML, usa el comando gcloud spanner databases execute-sql. En el siguiente ejemplo, se agrega una fila nueva a la tabla Singers.
gcloud spanner databases execute-sql example-db --instance=test-instance \
--sql="INSERT Singers (SingerId, FirstName, LastName) VALUES (1, 'Marc', 'Richards')"
Modifica datos con la biblioteca cliente
Para ejecutar declaraciones DML con la biblioteca cliente, sigue estos pasos:
- Crea una transacción de lectura y escritura.
- Llama al método de la biblioteca cliente para la ejecución de DML y pasa la declaración DML.
- Usa el valor que se muestra del método de ejecución de DML para obtener la cantidad de filas insertadas, actualizadas o borradas.
Con el siguiente ejemplo de código, se inserta una fila nueva en la tabla Singers.
C++
Usa la función ExecuteDml() para ejecutar una declaración DML.
void DmlStandardInsert(google::cloud::spanner::Client client) {
using ::google::cloud::StatusOr;
namespace spanner = ::google::cloud::spanner;
std::int64_t rows_inserted;
auto commit_result = client.Commit(
[&client, &rows_inserted](
spanner::Transaction txn) -> StatusOr<spanner::Mutations> {
auto insert = client.ExecuteDml(
std::move(txn),
spanner::SqlStatement(
"INSERT INTO Singers (SingerId, FirstName, LastName)"
" VALUES (10, 'Virginia', 'Watson')"));
if (!insert) return std::move(insert).status();
rows_inserted = insert->RowsModified();
return spanner::Mutations{};
});
if (!commit_result) throw std::move(commit_result).status();
std::cout << "Rows inserted: " << rows_inserted;
std::cout << "Insert was successful [spanner_dml_standard_insert]\n";
}C#
Usa el método ExecuteNonQueryAsync() para ejecutar una declaración DML.
using Google.Cloud.Spanner.Data;
using System;
using System.Threading.Tasks;
public class InsertUsingDmlCoreAsyncSample
{
public async Task<int> InsertUsingDmlCoreAsync(string projectId, string instanceId, string databaseId)
{
string connectionString = $"Data Source=projects/{projectId}/instances/{instanceId}/databases/{databaseId}";
using var connection = new SpannerConnection(connectionString);
await connection.OpenAsync();
using var cmd = connection.CreateDmlCommand("INSERT Singers (SingerId, FirstName, LastName) VALUES (10, 'Virginia', 'Watson')");
int rowCount = await cmd.ExecuteNonQueryAsync();
Console.WriteLine($"{rowCount} row(s) inserted...");
return rowCount;
}
}Go
Usa el método Update() para ejecutar una declaración DML.
import (
"context"
"fmt"
"io"
"cloud.google.com/go/spanner"
)
func insertUsingDML(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 {
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
Usa el método executeUpdate() para ejecutar una declaración DML.
static void insertUsingDml(DatabaseClient dbClient) {
dbClient
.readWriteTransaction()
.run(transaction -> {
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
Usa el método runUpdate() para ejecutar una declaración 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 ${rowCount} record into the Singers table.`
);
await transaction.commit();
} catch (err) {
console.error('ERROR:', err);
} finally {
// Close the database when finished.
database.close();
}
});PHP
Usa el método executeUpdate() para ejecutar una declaración DML.
use Google\Cloud\Spanner\SpannerClient;
use Google\Cloud\Spanner\Transaction;
/**
* Inserts sample data into the given database with a DML statement.
*
* The database and table must already exist and can be created using
* `create_database`.
* Example:
* ```
* insert_data($instanceId, $databaseId);
* ```
*
* @param string $instanceId The Spanner instance ID.
* @param string $databaseId The Spanner database ID.
*/
function insert_data_with_dml(string $instanceId, string $databaseId): void
{
$spanner = new SpannerClient();
$instance = $spanner->instance($instanceId);
$database = $instance->database($databaseId);
$database->runTransaction(function (Transaction $t) {
$rowCount = $t->executeUpdate(
'INSERT Singers (SingerId, FirstName, LastName) '
. " VALUES (10, 'Virginia', 'Watson')");
$t->commit();
printf('Inserted %d row(s).' . PHP_EOL, $rowCount);
});
}Python
Usa el método execute_update() para ejecutar una declaración 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 INTO Singers (SingerId, FirstName, LastName) "
" VALUES (10, 'Virginia', 'Watson')"
)
print("{} record(s) inserted.".format(row_ct))
database.run_in_transaction(insert_singers)Rita
Usa el método execute_update() para ejecutar una declaración 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."En el siguiente ejemplo de código, se actualiza la columna MarketingBudget de la tabla Albums según una cláusula WHERE.
C++
void DmlStandardUpdate(google::cloud::spanner::Client client) {
using ::google::cloud::StatusOr;
namespace spanner = ::google::cloud::spanner;
auto commit_result = client.Commit(
[&client](spanner::Transaction txn) -> StatusOr<spanner::Mutations> {
auto update = client.ExecuteDml(
std::move(txn),
spanner::SqlStatement(
"UPDATE Albums SET MarketingBudget = MarketingBudget * 2"
" WHERE SingerId = 1 AND AlbumId = 1"));
if (!update) return std::move(update).status();
return spanner::Mutations{};
});
if (!commit_result) throw std::move(commit_result).status();
std::cout << "Update was successful [spanner_dml_standard_update]\n";
}C#
using Google.Cloud.Spanner.Data;
using System;
using System.Threading.Tasks;
public class UpdateUsingDmlCoreAsyncSample
{
public async Task<int> UpdateUsingDmlCoreAsync(string projectId, string instanceId, string databaseId)
{
string connectionString = $"Data Source=projects/{projectId}/instances/{instanceId}/databases/{databaseId}";
using var connection = new SpannerConnection(connectionString);
await connection.OpenAsync();
using var cmd = connection.CreateDmlCommand("UPDATE Albums SET MarketingBudget = MarketingBudget * 2 WHERE SingerId = 1 and AlbumId = 1");
int rowCount = await cmd.ExecuteNonQueryAsync();
Console.WriteLine($"{rowCount} row(s) updated...");
return rowCount;
}
}Go
import (
"context"
"fmt"
"io"
"cloud.google.com/go/spanner"
)
func updateUsingDML(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 {
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(transaction -> {
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(string $instanceId, string $databaseId): void
{
$spanner = new SpannerClient();
$instance = $spanner->instance($instanceId);
$database = $instance->database($databaseId);
$database->runTransaction(function (Transaction $t) {
$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)Rita
# 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."En el siguiente ejemplo de código, se borran todas las filas de la tabla Singers en las que la columna FirstName es Alice.
C++
void DmlStandardDelete(google::cloud::spanner::Client client) {
using ::google::cloud::StatusOr;
namespace spanner = ::google::cloud::spanner;
auto commit_result = client.Commit([&client](spanner::Transaction txn)
-> StatusOr<spanner::Mutations> {
auto dele = client.ExecuteDml(
std::move(txn),
spanner::SqlStatement("DELETE FROM Singers WHERE FirstName = 'Alice'"));
if (!dele) return std::move(dele).status();
return spanner::Mutations{};
});
if (!commit_result) throw std::move(commit_result).status();
std::cout << "Delete was successful [spanner_dml_standard_delete]\n";
}C#
using Google.Cloud.Spanner.Data;
using System;
using System.Threading.Tasks;
public class DeleteUsingDmlCoreAsyncSample
{
public async Task<int> DeleteUsingDmlCoreAsync(string projectId, string instanceId, string databaseId)
{
string connectionString = $"Data Source=projects/{projectId}/instances/{instanceId}/databases/{databaseId}";
using var connection = new SpannerConnection(connectionString);
await connection.OpenAsync();
using var cmd = connection.CreateDmlCommand("DELETE FROM Singers WHERE FirstName = 'Alice'");
int rowCount = await cmd.ExecuteNonQueryAsync();
Console.WriteLine($"{rowCount} row(s) deleted...");
return rowCount;
}
}Go
import (
"context"
"fmt"
"io"
"cloud.google.com/go/spanner"
)
func deleteUsingDML(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 {
stmt := spanner.Statement{SQL: `DELETE FROM 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(transaction -> {
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 FROM 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(string $instanceId, string $databaseId): void
{
$spanner = new SpannerClient();
$instance = $spanner->instance($instanceId);
$database = $instance->database($databaseId);
$database->runTransaction(function (Transaction $t) {
$rowCount = $t->executeUpdate(
"DELETE FROM 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 FROM Singers WHERE FirstName = 'Alice'"
)
print("{} record(s) deleted.".format(row_ct))
database.run_in_transaction(delete_singers)Rita
# 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."En el siguiente ejemplo, solo para bases de datos con dialecto de GoogleSQL, se usa un STRUCT con parámetros vinculados a fin de actualizar el LastName en las filas filtradas por FirstName y LastName.
GoogleSQL
C++
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#
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
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
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
// 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(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
# 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)Rita
# 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."Modificar datos con las declaraciones DML que se muestran
La cláusula THEN RETURN (bases de datos de dialecto de GoogleSQL) o la cláusula RETURNING (bases de datos de dialecto de PostgreSQL) se diseñó para situaciones en las que deseas recuperar datos de filas modificadas. Esto es muy útil cuando deseas ver valores no especificados en las declaraciones DML, los valores predeterminados o las columnas generadas.
Para ejecutar declaraciones DML que se muestran con la biblioteca cliente, haz lo siguiente:
- Crea una transacción de lectura y escritura.
- Llama al método de la biblioteca cliente para la ejecución de la consulta y pasa la declaración DML que se muestra para obtener los resultados.
En el siguiente ejemplo de código, se inserta una fila nueva en la tabla Singers y se muestra la columna FullName generada de los registros insertados.
GoogleSQL
C++
void InsertUsingDmlReturning(google::cloud::spanner::Client client) {
// Insert records into SINGERS table and return the generated column
// FullName of the inserted records using `THEN RETURN FullName`.
auto commit = client.Commit(
[&client](google::cloud::spanner::Transaction txn)
-> google::cloud::StatusOr<google::cloud::spanner::Mutations> {
auto sql = google::cloud::spanner::SqlStatement(R"""(
INSERT INTO Singers (SingerId, FirstName, LastName)
VALUES (12, 'Melissa', 'Garcia'),
(13, 'Russell', 'Morales'),
(14, 'Jacqueline', 'Long'),
(15, 'Dylan', 'Shaw')
THEN RETURN FullName
)""");
using RowType = std::tuple<std::string>;
auto rows = client.ExecuteQuery(std::move(txn), std::move(sql));
// Note: This mutator might be re-run, or its effects discarded, so
// changing non-transactional state (e.g., by producing output) is,
// in general, not something to be imitated.
for (auto& row : google::cloud::spanner::StreamOf<RowType>(rows)) {
if (!row) return std::move(row).status();
std::cout << "FullName: " << std::get<0>(*row) << "\n";
}
std::cout << "Inserted row(s) count: " << rows.RowsModified() << "\n";
return google::cloud::spanner::Mutations{};
});
if (!commit) throw std::move(commit).status();
}C#
using Google.Cloud.Spanner.Data;
using System;
using System.Collections.Generic;
using System.Threading.Tasks;
public class InsertUsingDmlReturningAsyncSample
{
public async Task<List<string>> InsertUsingDmlReturningAsync(string projectId, string instanceId, string databaseId)
{
string connectionString = $"Data Source=projects/{projectId}/instances/{instanceId}/databases/{databaseId}";
using var connection = new SpannerConnection(connectionString);
await connection.OpenAsync();
// Insert records into the SINGERS table and return the
// generated column FullName of the inserted records using
// 'THEN RETURN FullName'.
// It is also possible to return all columns of all the
// inserted records by using 'THEN RETURN *'.
using var cmd = connection.CreateDmlCommand(
@"INSERT INTO Singers(SingerId, FirstName, LastName) VALUES
(6, 'Melissa', 'Garcia'),
(7, 'Russell', 'Morales'),
(8, 'Jacqueline', 'Long'),
(9, 'Dylan', 'Shaw') THEN RETURN FullName");
var reader = await cmd.ExecuteReaderAsync();
var insertedSingerNames = new List<string>();
while (await reader.ReadAsync())
{
insertedSingerNames.Add(reader.GetFieldValue<string>("FullName"));
}
Console.WriteLine($"{insertedSingerNames.Count} row(s) inserted...");
return insertedSingerNames;
}
}Go
import (
"context"
"fmt"
"io"
"cloud.google.com/go/spanner"
"google.golang.org/api/iterator"
)
func insertUsingDMLReturning(w io.Writer, db string) error {
ctx := context.Background()
client, err := spanner.NewClient(ctx, db)
if err != nil {
return err
}
defer client.Close()
// Insert records into the SINGERS table and returns the
// generated column FullName of the inserted records using
// 'THEN RETURN FullName'.
// It is also possible to return all columns of all the
// inserted records by using 'THEN RETURN *'.
_, err = client.ReadWriteTransaction(ctx, func(ctx context.Context, txn *spanner.ReadWriteTransaction) error {
stmt := spanner.Statement{
SQL: `INSERT INTO Singers (SingerId, FirstName, LastName)
VALUES (21, 'Melissa', 'Garcia'),
(22, 'Russell', 'Morales'),
(23, 'Jacqueline', 'Long'),
(24, 'Dylan', 'Shaw')
THEN RETURN FullName`,
}
iter := txn.Query(ctx, stmt)
defer iter.Stop()
for {
row, err := iter.Next()
if err == iterator.Done {
break
}
if err != nil {
return err
}
var fullName string
if err := row.Columns(&fullName); err != nil {
return err
}
fmt.Fprintf(w, "%s\n", fullName)
}
fmt.Fprintf(w, "%d record(s) inserted.\n", iter.RowCount)
return nil
})
return err
}
Java
import com.google.cloud.spanner.DatabaseClient;
import com.google.cloud.spanner.DatabaseId;
import com.google.cloud.spanner.ResultSet;
import com.google.cloud.spanner.Spanner;
import com.google.cloud.spanner.SpannerOptions;
import com.google.cloud.spanner.Statement;
public class InsertUsingDmlReturningSample {
static void insertUsingDmlReturning() {
// TODO(developer): Replace these variables before running the sample.
final String projectId = "my-project";
final String instanceId = "my-instance";
final String databaseId = "my-database";
insertUsingDmlReturning(projectId, instanceId, databaseId);
}
static void insertUsingDmlReturning(String projectId, String instanceId, String databaseId) {
try (Spanner spanner =
SpannerOptions.newBuilder()
.setProjectId(projectId)
.build()
.getService()) {
final DatabaseClient dbClient =
spanner.getDatabaseClient(DatabaseId.of(projectId, instanceId, databaseId));
// Insert records into the SINGERS table and returns the
// generated column FullName of the inserted records using
// ‘THEN RETURN FullName’.
// It is also possible to return all columns of all the
// inserted records by using ‘THEN RETURN *’.
dbClient
.readWriteTransaction()
.run(
transaction -> {
String sql =
"INSERT INTO Singers (SingerId, FirstName, LastName) VALUES "
+ "(12, 'Melissa', 'Garcia'), "
+ "(13, 'Russell', 'Morales'), "
+ "(14, 'Jacqueline', 'Long'), "
+ "(15, 'Dylan', 'Shaw') THEN RETURN FullName";
// readWriteTransaction.executeQuery(..) API should be used for executing
// DML statements with RETURNING clause.
try (ResultSet resultSet = transaction.executeQuery(Statement.of(sql))) {
while (resultSet.next()) {
System.out.println(resultSet.getString(0));
}
System.out.printf(
"Inserted row(s) count: %d\n", resultSet.getStats().getRowCountExact());
}
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,
});
function insertUsingDmlReturning(instanceId, databaseId) {
// 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 [rows, stats] = await transaction.run({
sql: 'INSERT Singers (SingerId, FirstName, LastName) VALUES (@id, @firstName, @lastName) THEN RETURN FullName',
params: {
id: 18,
firstName: 'Virginia',
lastName: 'Watson',
},
});
const rowCount = Math.floor(stats[stats.rowCount]);
console.log(
`Successfully inserted ${rowCount} record into the Singers table.`
);
rows.forEach(row => {
console.log(row.toJSON().FullName);
});
await transaction.commit();
} catch (err) {
console.error('ERROR:', err);
} finally {
// Close the database when finished.
database.close();
}
});
}
insertUsingDmlReturning(instanceId, databaseId);PHP
use Google\Cloud\Spanner\SpannerClient;
/**
* Inserts sample data into the given database using DML returning.
*
* @param string $instanceId The Spanner instance ID.
* @param string $databaseId The Spanner database ID.
*/
function insert_dml_returning(string $instanceId, string $databaseId): void
{
$spanner = new SpannerClient();
$instance = $spanner->instance($instanceId);
$database = $instance->database($databaseId);
// Insert records into SINGERS table and returns the generated column
// FullName of the inserted records using ‘THEN RETURN FullName’. It is also
// possible to return all columns of all the inserted records by using
// ‘THEN RETURN *’.
$sql = 'INSERT INTO Singers (SingerId, FirstName, LastName) '
. "VALUES (12, 'Melissa', 'Garcia'), "
. "(13, 'Russell', 'Morales'), "
. "(14, 'Jacqueline', 'Long'), "
. "(15, 'Dylan', 'Shaw') "
. 'THEN RETURN FullName';
$transaction = $database->transaction();
$result = $transaction->execute($sql);
foreach ($result->rows() as $row) {
printf(
'%s inserted.' . PHP_EOL,
$row['FullName'],
);
}
printf(
'Inserted row(s) count: %d' . PHP_EOL,
$result->stats()['rowCountExact']
);
$transaction->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)
# Insert records into the SINGERS table and returns the
# generated column FullName of the inserted records using
# 'THEN RETURN FullName'.
# It is also possible to return all columns of all the
# inserted records by using 'THEN RETURN *'.
def insert_singers(transaction):
results = transaction.execute_sql(
"INSERT INTO Singers (SingerId, FirstName, LastName) VALUES "
"(21, 'Luann', 'Chizoba'), "
"(22, 'Denis', 'Patricio'), "
"(23, 'Felxi', 'Ronan'), "
"(24, 'Dominik', 'Martyna') "
"THEN RETURN FullName"
)
for result in results:
print("FullName: {}".format(*result))
print("{} record(s) inserted.".format(results.stats.row_count_exact))
database.run_in_transaction(insert_singers)Rita
require "google/cloud/spanner"
##
# This is a snippet for showcasing how to use DML return feature with insert
# operation.
#
# @param project_id [String] The ID of the Google Cloud project.
# @param instance_id [String] The ID of the spanner instance.
# @param database_id [String] The ID of the database.
#
def spanner_insert_dml_returning project_id:, instance_id:, database_id:
spanner = Google::Cloud::Spanner.new project: project_id
client = spanner.client instance_id, database_id
client.transaction do |transaction|
# Insert records into the SINGERS table and returns the generated column
# FullName of the inserted records using ‘THEN RETURN FullName’.
# It is also possible to return all columns of all the inserted records
# by using ‘THEN RETURN *’.
results = transaction.execute_query "INSERT INTO Singers (SingerId, FirstName, LastName)
VALUES (12, 'Melissa', 'Garcia'), (13, 'Russell', 'Morales'), (14, 'Jacqueline', 'Long'), (15, 'Dylan', 'Shaw')
THEN RETURN FullName"
results.rows.each do |row|
puts "Inserted singers with FullName: #{row[:FullName]}"
end
puts "Inserted row(s) count: #{results.row_count}"
end
end
PostgreSQL
C++
void InsertUsingDmlReturning(google::cloud::spanner::Client client) {
// Insert records into SINGERS table and return the generated column
// FullName of the inserted records using `RETURNING FullName`.
auto commit = client.Commit(
[&client](google::cloud::spanner::Transaction txn)
-> google::cloud::StatusOr<google::cloud::spanner::Mutations> {
auto sql = google::cloud::spanner::SqlStatement(R"""(
INSERT INTO Singers (SingerId, FirstName, LastName)
VALUES (12, 'Melissa', 'Garcia'),
(13, 'Russell', 'Morales'),
(14, 'Jacqueline', 'Long'),
(15, 'Dylan', 'Shaw')
RETURNING FullName
)""");
using RowType = std::tuple<std::string>;
auto rows = client.ExecuteQuery(std::move(txn), std::move(sql));
for (auto& row : google::cloud::spanner::StreamOf<RowType>(rows)) {
if (!row) return std::move(row).status();
std::cout << "FullName: " << std::get<0>(*row) << "\n";
}
std::cout << "Inserted row(s) count: " << rows.RowsModified() << "\n";
return google::cloud::spanner::Mutations{};
});
if (!commit) throw std::move(commit).status();
}C#
using Google.Cloud.Spanner.Data;
using System;
using System.Collections.Generic;
using System.Threading.Tasks;
public class InsertUsingDmlReturningAsyncPostgresSample
{
public async Task<List<string>> InsertUsingDmlReturningAsyncPostgres(string projectId, string instanceId, string databaseId)
{
string connectionString = $"Data Source=projects/{projectId}/instances/{instanceId}/databases/{databaseId}";
using var connection = new SpannerConnection(connectionString);
await connection.OpenAsync();
// Insert records into SINGERS table and return the
// generated column FullName of the inserted records
// using 'RETURNING FullName'.
// It is also possible to return all columns of all the
// inserted records by using 'RETURNING *'.
using var cmd = connection.CreateDmlCommand(
@"INSERT INTO Singers(SingerId, FirstName, LastName) VALUES
(6, 'Melissa', 'Garcia'),
(7, 'Russell', 'Morales'),
(8, 'Jacqueline', 'Long'),
(9, 'Dylan', 'Shaw') RETURNING FullName");
var reader = await cmd.ExecuteReaderAsync();
var insertedSingerNames = new List<string>();
while (await reader.ReadAsync())
{
insertedSingerNames.Add(reader.GetFieldValue<string>("fullname"));
}
Console.WriteLine($"{insertedSingerNames.Count} row(s) inserted...");
return insertedSingerNames;
}
}Go
import (
"context"
"fmt"
"io"
"cloud.google.com/go/spanner"
"google.golang.org/api/iterator"
)
func pgInsertUsingDMLReturning(w io.Writer, db string) error {
ctx := context.Background()
client, err := spanner.NewClient(ctx, db)
if err != nil {
return err
}
defer client.Close()
// Insert records into the SINGERS table and returns the
// generated column FullName of the inserted records using
// 'RETURNING FullName'.
// It is also possible to return all columns of all the
// inserted records by using 'RETURNING *'.
_, err = client.ReadWriteTransaction(ctx, func(ctx context.Context, txn *spanner.ReadWriteTransaction) error {
stmt := spanner.Statement{
SQL: `INSERT INTO Singers (SingerId, FirstName, LastName)
VALUES (21, 'Melissa', 'Garcia'),
(22, 'Russell', 'Morales'),
(23, 'Jacqueline', 'Long'),
(24, 'Dylan', 'Shaw')
RETURNING FullName`,
}
iter := txn.Query(ctx, stmt)
defer iter.Stop()
for {
row, err := iter.Next()
if err == iterator.Done {
break
}
if err != nil {
return err
}
var fullName string
if err := row.Columns(&fullName); err != nil {
return err
}
fmt.Fprintf(w, "%s\n", fullName)
}
fmt.Fprintf(w, "%d record(s) inserted.\n", iter.RowCount)
return nil
})
return err
}
Java
import com.google.cloud.spanner.DatabaseClient;
import com.google.cloud.spanner.DatabaseId;
import com.google.cloud.spanner.ResultSet;
import com.google.cloud.spanner.Spanner;
import com.google.cloud.spanner.SpannerOptions;
import com.google.cloud.spanner.Statement;
public class PgInsertUsingDmlReturningSample {
static void insertUsingDmlReturning() {
// TODO(developer): Replace these variables before running the sample.
final String projectId = "my-project";
final String instanceId = "my-instance";
final String databaseId = "my-database";
insertUsingDmlReturning(projectId, instanceId, databaseId);
}
static void insertUsingDmlReturning(String projectId, String instanceId, String databaseId) {
try (Spanner spanner =
SpannerOptions.newBuilder()
.setProjectId(projectId)
.build()
.getService()) {
final DatabaseClient dbClient =
spanner.getDatabaseClient(DatabaseId.of(projectId, instanceId, databaseId));
// Insert records into SINGERS table and returns the
// generated column FullName of the inserted records
// using ‘RETURNING FullName’.
// It is also possible to return all columns of all the
// inserted records by using ‘RETURNING *’.
dbClient
.readWriteTransaction()
.run(
transaction -> {
String sql =
"INSERT INTO Singers (SingerId, FirstName, LastName) VALUES "
+ "(12, 'Melissa', 'Garcia'), "
+ "(13, 'Russell', 'Morales'), "
+ "(14, 'Jacqueline', 'Long'), "
+ "(15, 'Dylan', 'Shaw') RETURNING FullName";
// readWriteTransaction.executeQuery(..) API should be used for executing
// DML statements with RETURNING clause.
try (ResultSet resultSet = transaction.executeQuery(Statement.of(sql))) {
while (resultSet.next()) {
System.out.println(resultSet.getString(0));
}
System.out.printf(
"Inserted row(s) count: %d\n", resultSet.getStats().getRowCountExact());
}
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,
});
function pgInsertUsingDmlReturning(instanceId, databaseId) {
// 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 [rows, stats] = await transaction.run({
sql: 'INSERT Into Singers (SingerId, FirstName, LastName) VALUES ($1, $2, $3) RETURNING FullName',
params: {
p1: 18,
p2: 'Virginia',
p3: 'Watson',
},
});
const rowCount = Math.floor(stats[stats.rowCount]);
console.log(
`Successfully inserted ${rowCount} record into the Singers table.`
);
rows.forEach(row => {
console.log(row.toJSON().fullname);
});
await transaction.commit();
} catch (err) {
console.error('ERROR:', err);
} finally {
// Close the database when finished.
database.close();
}
});
}
pgInsertUsingDmlReturning(instanceId, databaseId);PHP
use Google\Cloud\Spanner\SpannerClient;
/**
* Inserts sample data into the given postgresql database using DML returning.
*
* @param string $instanceId The Spanner instance ID.
* @param string $databaseId The Spanner database ID.
*/
function pg_insert_dml_returning(string $instanceId, string $databaseId): void
{
$spanner = new SpannerClient();
$instance = $spanner->instance($instanceId);
$database = $instance->database($databaseId);
// Insert records into SINGERS table and returns the generated column
// FullName of the inserted records using ‘RETURNING FullName’. It is also
// possible to return all columns of all the inserted records by using
// ‘RETURNING *’.
$sql = 'INSERT INTO Singers (Singerid, FirstName, LastName) '
. "VALUES (12, 'Melissa', 'Garcia'), "
. "(13, 'Russell', 'Morales'), "
. "(14, 'Jacqueline', 'Long'), "
. "(15, 'Dylan', 'Shaw') "
. 'RETURNING FullName';
$transaction = $database->transaction();
$result = $transaction->execute($sql);
foreach ($result->rows() as $row) {
printf(
'%s inserted.' . PHP_EOL,
$row['fullname'],
);
}
printf(
'Inserted row(s) count: %d' . PHP_EOL,
$result->stats()['rowCountExact']
);
$transaction->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)
# Insert records into the SINGERS table and returns the
# generated column FullName of the inserted records using
# 'RETURNING FullName'.
# It is also possible to return all columns of all the
# inserted records by using 'RETURNING *'.
def insert_singers(transaction):
results = transaction.execute_sql(
"INSERT INTO Singers (SingerId, FirstName, LastName) VALUES "
"(21, 'Luann', 'Chizoba'), "
"(22, 'Denis', 'Patricio'), "
"(23, 'Felxi', 'Ronan'), "
"(24, 'Dominik', 'Martyna') "
"RETURNING FullName"
)
for result in results:
print("FullName: {}".format(*result))
print("{} record(s) inserted.".format(results.stats.row_count_exact))
database.run_in_transaction(insert_singers)Rita
require "google/cloud/spanner"
##
# This is a snippet for showcasing how to use DML return feature with insert
# operation in PostgreSql.
#
# @param project_id [String] The ID of the Google Cloud project.
# @param instance_id [String] The ID of the spanner instance.
# @param database_id [String] The ID of the database.
#
def spanner_postgresql_insert_dml_returning project_id:, instance_id:, database_id:
spanner = Google::Cloud::Spanner.new project: project_id
client = spanner.client instance_id, database_id
client.transaction do |transaction|
# Insert records into SINGERS table and returns the generated column
# FullName of the inserted records using ‘RETURNING FullName’.
# It is also possible to return all columns of all the inserted
# records by using ‘RETURNING *’.
results = transaction.execute_query "INSERT INTO Singers (SingerId, FirstName, LastName)
VALUES (12, 'Melissa', 'Garcia'), (13, 'Russell', 'Morales'), (14, 'Jacqueline', 'Long'), (15, 'Dylan', 'Shaw')
RETURNING FullName"
results.rows.each do |row|
puts "Inserted singers with FullName: #{row[:fullname]}"
end
puts "Inserted row(s) count: #{results.row_count}"
end
end
En el siguiente ejemplo de código, se actualiza la columna MarketingBudget de la tabla Albums según una cláusula WHERE y se muestra la columna MarketingBudget modificada de los registros actualizados.
GoogleSQL
C++
void UpdateUsingDmlReturning(google::cloud::spanner::Client client) {
// Update MarketingBudget column for records satisfying a particular
// condition and return the modified MarketingBudget column of the
// updated records using `THEN RETURN MarketingBudget`.
auto commit = client.Commit(
[&client](google::cloud::spanner::Transaction txn)
-> google::cloud::StatusOr<google::cloud::spanner::Mutations> {
auto sql = google::cloud::spanner::SqlStatement(R"""(
UPDATE Albums SET MarketingBudget = MarketingBudget * 2
WHERE SingerId = 1 AND AlbumId = 1
THEN RETURN MarketingBudget
)""");
using RowType = std::tuple<absl::optional<std::int64_t>>;
auto rows = client.ExecuteQuery(std::move(txn), std::move(sql));
// Note: This mutator might be re-run, or its effects discarded, so
// changing non-transactional state (e.g., by producing output) is,
// in general, not something to be imitated.
for (auto& row : google::cloud::spanner::StreamOf<RowType>(rows)) {
if (!row) return std::move(row).status();
std::cout << "MarketingBudget: ";
if (std::get<0>(*row).has_value()) {
std::cout << *std::get<0>(*row);
} else {
std::cout << "NULL";
}
std::cout << "\n";
}
std::cout << "Updated row(s) count: " << rows.RowsModified() << "\n";
return google::cloud::spanner::Mutations{};
});
if (!commit) throw std::move(commit).status();
}C#
using Google.Cloud.Spanner.Data;
using System;
using System.Collections.Generic;
using System.Threading.Tasks;
public class UpdateUsingDmlReturningAsyncSample
{
public async Task<List<long>> UpdateUsingDmlReturningAsync(string projectId, string instanceId, string databaseId)
{
string connectionString = $"Data Source=projects/{projectId}/instances/{instanceId}/databases/{databaseId}";
using var connection = new SpannerConnection(connectionString);
await connection.OpenAsync();
// Update MarketingBudget column for records satisfying
// a particular condition and return the modified
// MarketingBudget column of the updated records using
// 'THEN RETURN MarketingBudget'.
// It is also possible to return all columns of all the
// updated records by using 'THEN RETURN *'.
using var cmd = connection.CreateDmlCommand("UPDATE Albums SET MarketingBudget = MarketingBudget * 2 WHERE SingerId = 1 and AlbumId = 1 THEN RETURN MarketingBudget");
var reader = await cmd.ExecuteReaderAsync();
var updatedMarketingBudgets = new List<long>();
while (await reader.ReadAsync())
{
updatedMarketingBudgets.Add(reader.GetFieldValue<long>("MarketingBudget"));
}
Console.WriteLine($"{updatedMarketingBudgets.Count} row(s) updated...");
return updatedMarketingBudgets;
}
}Go
import (
"context"
"fmt"
"io"
"cloud.google.com/go/spanner"
"google.golang.org/api/iterator"
)
func updateUsingDMLReturning(w io.Writer, db string) error {
ctx := context.Background()
client, err := spanner.NewClient(ctx, db)
if err != nil {
return err
}
defer client.Close()
// Update MarketingBudget column for records satisfying
// a particular condition and returns the modified
// MarketingBudget column of the updated records using
// 'THEN RETURN MarketingBudget'.
// It is also possible to return all columns of all the
// updated records by using 'THEN RETURN *'.
_, 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
THEN RETURN MarketingBudget`,
}
iter := txn.Query(ctx, stmt)
defer iter.Stop()
for {
row, err := iter.Next()
if err == iterator.Done {
break
}
if err != nil {
return err
}
var marketingBudget int64
if err := row.Columns(&marketingBudget); err != nil {
return err
}
fmt.Fprintf(w, "%d\n", marketingBudget)
}
fmt.Fprintf(w, "%d record(s) updated.\n", iter.RowCount)
return nil
})
return err
}
Java
import com.google.cloud.spanner.DatabaseClient;
import com.google.cloud.spanner.DatabaseId;
import com.google.cloud.spanner.ResultSet;
import com.google.cloud.spanner.Spanner;
import com.google.cloud.spanner.SpannerOptions;
import com.google.cloud.spanner.Statement;
public class UpdateUsingDmlReturningSample {
static void updateUsingDmlReturning() {
// TODO(developer): Replace these variables before running the sample.
final String projectId = "my-project";
final String instanceId = "my-instance";
final String databaseId = "my-database";
updateUsingDmlReturning(projectId, instanceId, databaseId);
}
static void updateUsingDmlReturning(String projectId, String instanceId, String databaseId) {
try (Spanner spanner =
SpannerOptions.newBuilder()
.setProjectId(projectId)
.build()
.getService()) {
final DatabaseClient dbClient =
spanner.getDatabaseClient(DatabaseId.of(projectId, instanceId, databaseId));
// Update MarketingBudget column for records satisfying
// a particular condition and returns the modified
// MarketingBudget column of the updated records using
// ‘THEN RETURN MarketingBudget’.
// It is also possible to return all columns of all the
// updated records by using ‘THEN RETURN *’.
dbClient
.readWriteTransaction()
.run(
transaction -> {
String sql =
"UPDATE Albums "
+ "SET MarketingBudget = MarketingBudget * 2 "
+ "WHERE SingerId = 1 and AlbumId = 1 "
+ "THEN RETURN MarketingBudget";
// readWriteTransaction.executeQuery(..) API should be used for executing
// DML statements with RETURNING clause.
try (ResultSet resultSet = transaction.executeQuery(Statement.of(sql))) {
while (resultSet.next()) {
System.out.printf("%d\n", resultSet.getLong(0));
}
System.out.printf(
"Updated row(s) count: %d\n", resultSet.getStats().getRowCountExact());
}
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,
});
function updateUsingDmlReturning(instanceId, databaseId) {
// 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 [rows, stats] = await transaction.run({
sql: 'UPDATE Albums SET MarketingBudget = 2000000 WHERE SingerId = 1 and AlbumId = 1 THEN RETURN MarketingBudget',
});
const rowCount = Math.floor(stats[stats.rowCount]);
console.log(
`Successfully updated ${rowCount} record into the Albums table.`
);
rows.forEach(row => {
console.log(row.toJSON().MarketingBudget);
});
await transaction.commit();
} catch (err) {
console.error('ERROR:', err);
} finally {
// Close the database when finished.
database.close();
}
});
}
updateUsingDmlReturning(instanceId, databaseId);PHP
use Google\Cloud\Spanner\SpannerClient;
/**
* Update the given database using DML returning.
*
* @param string $instanceId The Spanner instance ID.
* @param string $databaseId The Spanner database ID.
*/
function update_dml_returning(string $instanceId, string $databaseId): void
{
$spanner = new SpannerClient();
$instance = $spanner->instance($instanceId);
$database = $instance->database($databaseId);
$transaction = $database->transaction();
// Update MarketingBudget column for records satisfying a particular
// condition and returns the modified MarketingBudget column of the updated
// records using ‘THEN RETURN MarketingBudget’. It is also possible to return
// all columns of all the updated records by using ‘THEN RETURN *’.
$result = $transaction->execute(
'UPDATE Albums '
. 'SET MarketingBudget = MarketingBudget * 2 '
. 'WHERE SingerId = 1 and AlbumId = 1 '
. 'THEN RETURN MarketingBudget'
);
foreach ($result->rows() as $row) {
printf('MarketingBudget: %s' . PHP_EOL, $row['MarketingBudget']);
}
printf(
'Updated row(s) count: %d' . PHP_EOL,
$result->stats()['rowCountExact']
);
$transaction->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)
# Update MarketingBudget column for records satisfying
# a particular condition and returns the modified
# MarketingBudget column of the updated records using
# 'THEN RETURN MarketingBudget'.
# It is also possible to return all columns of all the
# updated records by using 'THEN RETURN *'.
def update_albums(transaction):
results = transaction.execute_sql(
"UPDATE Albums "
"SET MarketingBudget = MarketingBudget * 2 "
"WHERE SingerId = 1 and AlbumId = 1 "
"THEN RETURN MarketingBudget"
)
for result in results:
print("MarketingBudget: {}".format(*result))
print("{} record(s) updated.".format(results.stats.row_count_exact))
database.run_in_transaction(update_albums)Rita
require "google/cloud/spanner"
##
# This is a snippet for showcasing how to use DML return feature with update
# operation.
#
# @param project_id [String] The ID of the Google Cloud project.
# @param instance_id [String] The ID of the spanner instance.
# @param database_id [String] The ID of the database.
#
def spanner_update_dml_returning project_id:, instance_id:, database_id:
spanner = Google::Cloud::Spanner.new project: project_id
client = spanner.client instance_id, database_id
client.transaction do |transaction|
# Update MarketingBudget column for records satisfying a particular
# condition and returns the modified MarketingBudget column of the
# updated records using ‘THEN RETURN MarketingBudget’.
#
# It is also possible to return all columns of all the updated records
# by using ‘THEN RETURN *’.
results = transaction.execute_query "UPDATE Albums SET MarketingBudget = MarketingBudget * 2
WHERE SingerId = 1 and AlbumId = 1
THEN RETURN MarketingBudget"
results.rows.each do |row|
puts "Updated Album with MarketingBudget: #{row[:MarketingBudget]}"
end
puts "Updated row(s) count: #{results.row_count}"
end
end
PostgreSQL
C++
void UpdateUsingDmlReturning(google::cloud::spanner::Client client) {
// Update MarketingBudget column for records satisfying a particular
// condition and return the modified MarketingBudget column of the
// updated records using `RETURNING MarketingBudget`.
auto commit = client.Commit(
[&client](google::cloud::spanner::Transaction txn)
-> google::cloud::StatusOr<google::cloud::spanner::Mutations> {
auto sql = google::cloud::spanner::SqlStatement(R"""(
UPDATE Albums SET MarketingBudget = MarketingBudget * 2
WHERE SingerId = 1 AND AlbumId = 1
RETURNING MarketingBudget
)""");
using RowType = std::tuple<absl::optional<std::int64_t>>;
auto rows = client.ExecuteQuery(std::move(txn), std::move(sql));
for (auto& row : google::cloud::spanner::StreamOf<RowType>(rows)) {
if (!row) return std::move(row).status();
std::cout << "MarketingBudget: ";
if (std::get<0>(*row).has_value()) {
std::cout << *std::get<0>(*row);
} else {
std::cout << "NULL";
}
std::cout << "\n";
}
std::cout << "Updated row(s) count: " << rows.RowsModified() << "\n";
return google::cloud::spanner::Mutations{};
});
if (!commit) throw std::move(commit).status();
}C#
using Google.Cloud.Spanner.Data;
using System;
using System.Collections.Generic;
using System.Threading.Tasks;
public class UpdateUsingDmlReturningAsyncPostgresSample
{
public async Task<List<long>> UpdateUsingDmlReturningAsyncPostgres(string projectId, string instanceId, string databaseId)
{
string connectionString = $"Data Source=projects/{projectId}/instances/{instanceId}/databases/{databaseId}";
using var connection = new SpannerConnection(connectionString);
await connection.OpenAsync();
// Update MarketingBudget column for records satisfying
// a particular condition and return the modified
// MarketingBudget column of the updated records using
// 'RETURNING MarketingBudget'.
// It is also possible to return all columns of all the
// updated records by using 'RETURNING *'.
using var cmd = connection.CreateDmlCommand("UPDATE Albums SET MarketingBudget = MarketingBudget * 2 WHERE SingerId = 14 and AlbumId = 20 RETURNING MarketingBudget");
var reader = await cmd.ExecuteReaderAsync();
var updatedMarketingBudgets = new List<long>();
while (await reader.ReadAsync())
{
updatedMarketingBudgets.Add(reader.GetFieldValue<long>("marketingbudget"));
}
Console.WriteLine($"{updatedMarketingBudgets.Count} row(s) updated...");
return updatedMarketingBudgets;
}
}Go
import (
"context"
"fmt"
"io"
"cloud.google.com/go/spanner"
"google.golang.org/api/iterator"
)
func pgUpdateUsingDMLReturning(w io.Writer, db string) error {
ctx := context.Background()
client, err := spanner.NewClient(ctx, db)
if err != nil {
return err
}
defer client.Close()
// Update MarketingBudget column for records satisfying
// a particular condition and returns the modified
// MarketingBudget column of the updated records using
// 'RETURNING MarketingBudget'.
// It is also possible to return all columns of all the
// updated records by using 'RETURNING *'.
_, 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
RETURNING MarketingBudget`,
}
iter := txn.Query(ctx, stmt)
defer iter.Stop()
for {
row, err := iter.Next()
if err == iterator.Done {
break
}
if err != nil {
return err
}
var marketingBudget int64
if err := row.Columns(&marketingBudget); err != nil {
return err
}
fmt.Fprintf(w, "%d\n", marketingBudget)
}
fmt.Fprintf(w, "%d record(s) updated.\n", iter.RowCount)
return nil
})
return err
}
Java
import com.google.cloud.spanner.DatabaseClient;
import com.google.cloud.spanner.DatabaseId;
import com.google.cloud.spanner.ResultSet;
import com.google.cloud.spanner.Spanner;
import com.google.cloud.spanner.SpannerOptions;
import com.google.cloud.spanner.Statement;
public class PgUpdateUsingDmlReturningSample {
static void updateUsingDmlReturning() {
// TODO(developer): Replace these variables before running the sample.
final String projectId = "my-project";
final String instanceId = "my-instance";
final String databaseId = "my-database";
updateUsingDmlReturning(projectId, instanceId, databaseId);
}
static void updateUsingDmlReturning(String projectId, String instanceId, String databaseId) {
try (Spanner spanner =
SpannerOptions.newBuilder()
.setProjectId(projectId)
.build()
.getService()) {
final DatabaseClient dbClient =
spanner.getDatabaseClient(DatabaseId.of(projectId, instanceId, databaseId));
// Update MarketingBudget column for records satisfying
// a particular condition and returns the modified
// MarketingBudget column of the updated records using
// ‘RETURNING MarketingBudget’.
// It is also possible to return all columns of all the
// updated records by using ‘RETURNING *’.
dbClient
.readWriteTransaction()
.run(
transaction -> {
String sql =
"UPDATE Albums "
+ "SET MarketingBudget = MarketingBudget * 2 "
+ "WHERE SingerId = 1 and AlbumId = 1 "
+ "RETURNING MarketingBudget";
// readWriteTransaction.executeQuery(..) API should be used for executing
// DML statements with RETURNING clause.
try (ResultSet resultSet = transaction.executeQuery(Statement.of(sql))) {
while (resultSet.next()) {
System.out.printf("%d\n", resultSet.getLong(0));
}
System.out.printf(
"Updated row(s) count: %d\n", resultSet.getStats().getRowCountExact());
}
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,
});
function pgUpdateUsingDmlReturning(instanceId, databaseId) {
// 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 [rows, stats] = await transaction.run({
sql: 'UPDATE singers SET FirstName = $1, LastName = $2 WHERE singerid = $3 RETURNING FullName',
params: {
p1: 'Virginia1',
p2: 'Watson1',
p3: 18,
},
});
const rowCount = Math.floor(stats[stats.rowCount]);
console.log(
`Successfully updated ${rowCount} record into the Singers table.`
);
rows.forEach(row => {
console.log(row.toJSON().fullname);
});
await transaction.commit();
} catch (err) {
console.error('ERROR:', err);
} finally {
// Close the database when finished.
database.close();
}
});
}
pgUpdateUsingDmlReturning(instanceId, databaseId);PHP
use Google\Cloud\Spanner\SpannerClient;
/**
* Update the given postgresql database using DML returning.
*
* @param string $instanceId The Spanner instance ID.
* @param string $databaseId The Spanner database ID.
*/
function pg_update_dml_returning(string $instanceId, string $databaseId): void
{
$spanner = new SpannerClient();
$instance = $spanner->instance($instanceId);
$database = $instance->database($databaseId);
$transaction = $database->transaction();
// Update MarketingBudget column for records satisfying a particular
// condition and returns the modified MarketingBudget column of the updated
// records using ‘RETURNING MarketingBudget’. It is also possible to return
// all columns of all the updated records by using ‘RETURNING *’.
$result = $transaction->execute(
'UPDATE Albums '
. 'SET MarketingBudget = MarketingBudget * 2 '
. 'WHERE SingerId = 1 and AlbumId = 1'
. 'RETURNING MarketingBudget'
);
foreach ($result->rows() as $row) {
printf('MarketingBudget: %s' . PHP_EOL, $row['marketingbudget']);
}
printf(
'Updated row(s) count: %d' . PHP_EOL,
$result->stats()['rowCountExact']
);
$transaction->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)
# Update MarketingBudget column for records satisfying
# a particular condition and returns the modified
# MarketingBudget column of the updated records using
# 'RETURNING MarketingBudget'.
# It is also possible to return all columns of all the
# updated records by using 'RETURNING *'.
def update_albums(transaction):
results = transaction.execute_sql(
"UPDATE Albums "
"SET MarketingBudget = MarketingBudget * 2 "
"WHERE SingerId = 1 and AlbumId = 1 "
"RETURNING MarketingBudget"
)
for result in results:
print("MarketingBudget: {}".format(*result))
print("{} record(s) updated.".format(results.stats.row_count_exact))
database.run_in_transaction(update_albums)Rita
require "google/cloud/spanner"
##
# This is a snippet for showcasing how to use DML return feature with update
# operation in PostgreSql.
#
# @param project_id [String] The ID of the Google Cloud project.
# @param instance_id [String] The ID of the spanner instance.
# @param database_id [String] The ID of the database.
#
def spanner_postgresql_update_dml_returning project_id:, instance_id:, database_id:
spanner = Google::Cloud::Spanner.new project: project_id
client = spanner.client instance_id, database_id
client.transaction do |transaction|
# Update MarketingBudget column for records satisfying a particular
# condition and returns the modified MarketingBudget column of the
# updated records using ‘RETURNING MarketingBudget’.
# It is also possible to return all columns of all the updated records
# by using ‘RETURNING *’.
results = transaction.execute_query "UPDATE Albums SET MarketingBudget = MarketingBudget * 2
WHERE SingerId = 1 and AlbumId = 1
RETURNING MarketingBudget"
results.rows.each do |row|
puts "Updated Albums with MarketingBudget: #{row[:marketingbudget]}"
end
puts "Updated row(s) count: #{results.row_count}"
end
end
En el siguiente ejemplo de código, se borran todas las filas de la tabla Singers en las que la columna FirstName es Alice y muestra las columnas SingerId y FullName de los registros borrados.
GoogleSQL
C++
void DeleteUsingDmlReturning(google::cloud::spanner::Client client) {
// Delete records from SINGERS table satisfying a particular condition
// and return the SingerId and FullName column of the deleted records
// using `THEN RETURN SingerId, FullName'.
auto commit = client.Commit(
[&client](google::cloud::spanner::Transaction txn)
-> google::cloud::StatusOr<google::cloud::spanner::Mutations> {
auto sql = google::cloud::spanner::SqlStatement(R"""(
DELETE FROM Singers
WHERE FirstName = 'Alice'
THEN RETURN SingerId, FullName
)""");
using RowType = std::tuple<std::int64_t, std::string>;
auto rows = client.ExecuteQuery(std::move(txn), std::move(sql));
// Note: This mutator might be re-run, or its effects discarded, so
// changing non-transactional state (e.g., by producing output) is,
// in general, not something to be imitated.
for (auto& row : google::cloud::spanner::StreamOf<RowType>(rows)) {
if (!row) return std::move(row).status();
std::cout << "SingerId: " << std::get<0>(*row) << " ";
std::cout << "FullName: " << std::get<1>(*row) << "\n";
}
std::cout << "Deleted row(s) count: " << rows.RowsModified() << "\n";
return google::cloud::spanner::Mutations{};
});
if (!commit) throw std::move(commit).status();
}C#
using Google.Cloud.Spanner.Data;
using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
public class DeleteUsingDmlReturningAsyncSample
{
public async Task<List<string>> DeleteUsingDmlReturningAsync(string projectId, string instanceId, string databaseId)
{
string connectionString = $"Data Source=projects/{projectId}/instances/{instanceId}/databases/{databaseId}";
using var connection = new SpannerConnection(connectionString);
await connection.OpenAsync();
// Delete records from SINGERS table satisfying a
// particular condition and return the SingerId
// and FullName column of the deleted records using
// 'THEN RETURN SingerId, FullName'.
// It is also possible to return all columns of all the
// deleted records by using 'THEN RETURN *'.
using var cmd = connection.CreateDmlCommand("DELETE FROM Singers WHERE FirstName = 'Alice' THEN RETURN SingerId, FullName");
var reader = await cmd.ExecuteReaderAsync();
var deletedSingerNames = new List<string>();
while (await reader.ReadAsync())
{
deletedSingerNames.Add(reader.GetFieldValue<string>("FullName"));
}
Console.WriteLine($"{deletedSingerNames.Count} row(s) deleted...");
return deletedSingerNames;
}
}Go
import (
"context"
"fmt"
"io"
"cloud.google.com/go/spanner"
"google.golang.org/api/iterator"
)
func deleteUsingDMLReturning(w io.Writer, db string) error {
ctx := context.Background()
client, err := spanner.NewClient(ctx, db)
if err != nil {
return err
}
defer client.Close()
// Delete records from SINGERS table satisfying a
// particular condition and returns the SingerId
// and FullName column of the deleted records using
// 'THEN RETURN SingerId, FullName'.
// It is also possible to return all columns of all the
// deleted records by using 'THEN RETURN *'.
_, err = client.ReadWriteTransaction(ctx, func(ctx context.Context, txn *spanner.ReadWriteTransaction) error {
stmt := spanner.Statement{
SQL: `DELETE FROM Singers WHERE FirstName = 'Alice'
THEN RETURN SingerId, FullName`,
}
iter := txn.Query(ctx, stmt)
defer iter.Stop()
for {
row, err := iter.Next()
if err == iterator.Done {
break
}
if err != nil {
return err
}
var (
singerID int64
fullName string
)
if err := row.Columns(&singerID, &fullName); err != nil {
return err
}
fmt.Fprintf(w, "%d %s\n", singerID, fullName)
}
fmt.Fprintf(w, "%d record(s) deleted.\n", iter.RowCount)
return nil
})
return err
}
Java
import com.google.cloud.spanner.DatabaseClient;
import com.google.cloud.spanner.DatabaseId;
import com.google.cloud.spanner.ResultSet;
import com.google.cloud.spanner.Spanner;
import com.google.cloud.spanner.SpannerOptions;
import com.google.cloud.spanner.Statement;
public class DeleteUsingDmlReturningSample {
static void deleteUsingDmlReturningSample() {
// TODO(developer): Replace these variables before running the sample.
final String projectId = "my-project";
final String instanceId = "my-instance";
final String databaseId = "my-database";
deleteUsingDmlReturningSample(projectId, instanceId, databaseId);
}
static void deleteUsingDmlReturningSample(
String projectId, String instanceId, String databaseId) {
try (Spanner spanner =
SpannerOptions.newBuilder()
.setProjectId(projectId)
.build()
.getService()) {
final DatabaseClient dbClient =
spanner.getDatabaseClient(DatabaseId.of(projectId, instanceId, databaseId));
// Delete records from SINGERS table satisfying a
// particular condition and returns the SingerId
// and FullName column of the deleted records using
// ‘THEN RETURN SingerId, FullName’.
// It is also possible to return all columns of all the
// deleted records by using ‘THEN RETURN *’.
dbClient
.readWriteTransaction()
.run(
transaction -> {
String sql =
"DELETE FROM Singers WHERE FirstName = 'Alice' THEN RETURN SingerId, FullName";
// readWriteTransaction.executeQuery(..) API should be used for executing
// DML statements with RETURNING clause.
try (ResultSet resultSet = transaction.executeQuery(Statement.of(sql))) {
while (resultSet.next()) {
System.out.printf("%d %s\n", resultSet.getLong(0), resultSet.getString(1));
}
System.out.printf(
"Deleted row(s) count: %d\n", resultSet.getStats().getRowCountExact());
}
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,
});
function deleteUsingDmlReturning(instanceId, databaseId) {
// 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 [rows, stats] = await transaction.run({
sql: 'DELETE FROM Singers WHERE SingerId = 18 THEN RETURN FullName',
});
const rowCount = Math.floor(stats[stats.rowCount]);
console.log(
`Successfully deleted ${rowCount} record from the Singers table.`
);
rows.forEach(row => {
console.log(row.toJSON().FullName);
});
await transaction.commit();
} catch (err) {
console.error('ERROR:', err);
} finally {
// Close the database when finished.
database.close();
}
});
}
deleteUsingDmlReturning(instanceId, databaseId);PHP
use Google\Cloud\Spanner\SpannerClient;
/**
* Delete data from the given database using DML returning.
*
* @param string $instanceId The Spanner instance ID.
* @param string $databaseId The Spanner database ID.
*/
function delete_dml_returning(string $instanceId, string $databaseId): void
{
$spanner = new SpannerClient();
$instance = $spanner->instance($instanceId);
$database = $instance->database($databaseId);
$transaction = $database->transaction();
// Delete records from SINGERS table satisfying a particular condition and
// returns the SingerId and FullName column of the deleted records using
// 'THEN RETURN SingerId, FullName'. It is also possible to return all columns
// of all the deleted records by using 'THEN RETURN *'.
$result = $transaction->execute(
"DELETE FROM Singers WHERE FirstName = 'Alice' "
. 'THEN RETURN SingerId, FullName',
);
foreach ($result->rows() as $row) {
printf(
'%d %s.' . PHP_EOL,
$row['SingerId'],
$row['FullName']
);
}
printf(
'Deleted row(s) count: %d' . PHP_EOL,
$result->stats()['rowCountExact']
);
$transaction->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)
# Delete records from SINGERS table satisfying a
# particular condition and returns the SingerId
# and FullName column of the deleted records using
# 'THEN RETURN SingerId, FullName'.
# It is also possible to return all columns of all the
# deleted records by using 'THEN RETURN *'.
def delete_singers(transaction):
results = transaction.execute_sql(
"DELETE FROM Singers WHERE FirstName = 'David' "
"THEN RETURN SingerId, FullName"
)
for result in results:
print("SingerId: {}, FullName: {}".format(*result))
print("{} record(s) deleted.".format(results.stats.row_count_exact))
database.run_in_transaction(delete_singers)Rita
require "google/cloud/spanner"
##
# This is a snippet for showcasing how to use DML return feature with delete
# operation.
#
# @param project_id [String] The ID of the Google Cloud project.
# @param instance_id [String] The ID of the spanner instance.
# @param database_id [String] The ID of the database.
#
def spanner_delete_dml_returning project_id:, instance_id:, database_id:
spanner = Google::Cloud::Spanner.new project: project_id
client = spanner.client instance_id, database_id
client.transaction do |transaction|
# Delete records from SINGERS table satisfying a particular condition and
# returns the SingerId and FullName column of the deleted records using
# ‘THEN RETURN SingerId, FullName’.
# It is also possible to return all columns of all the deleted records
# by using ‘THEN RETURN *’.
results = transaction.execute_query "DELETE FROM Singers WHERE FirstName = 'Alice' THEN RETURN SingerId, FullName"
results.rows.each do |row|
puts "Deleted singer with SingerId: #{row[:SingerId]}, FullName: #{row[:FullName]}"
end
puts "Deleted row(s) count: #{results.row_count}"
end
end
PostgreSQL
C++
void DeleteUsingDmlReturning(google::cloud::spanner::Client client) {
// Delete records from SINGERS table satisfying a particular condition
// and return the SingerId and FullName column of the deleted records
// using `RETURNING SingerId, FullName'.
auto commit = client.Commit(
[&client](google::cloud::spanner::Transaction txn)
-> google::cloud::StatusOr<google::cloud::spanner::Mutations> {
auto sql = google::cloud::spanner::SqlStatement(R"""(
DELETE FROM Singers
WHERE FirstName = 'Alice'
RETURNING SingerId, FullName
)""");
using RowType = std::tuple<std::int64_t, std::string>;
auto rows = client.ExecuteQuery(std::move(txn), std::move(sql));
for (auto& row : google::cloud::spanner::StreamOf<RowType>(rows)) {
if (!row) return std::move(row).status();
std::cout << "SingerId: " << std::get<0>(*row) << " ";
std::cout << "FullName: " << std::get<1>(*row) << "\n";
}
std::cout << "Deleted row(s) count: " << rows.RowsModified() << "\n";
return google::cloud::spanner::Mutations{};
});
if (!commit) throw std::move(commit).status();
}C#
using Google.Cloud.Spanner.Data;
using System;
using System.Collections.Generic;
using System.Threading.Tasks;
public class DeleteUsingDmlReturningAsyncPostgresSample
{
public async Task<List<string>> DeleteUsingDmlReturningAsyncPostgres(string projectId, string instanceId, string databaseId)
{
string connectionString = $"Data Source=projects/{projectId}/instances/{instanceId}/databases/{databaseId}";
using var connection = new SpannerConnection(connectionString);
await connection.OpenAsync();
// Delete records from SINGERS table satisfying a
// particular condition and return the SingerId
// and FullName column of the deleted records using
// 'RETURNING SingerId, FullName'.
// It is also possible to return all columns of all the
// deleted records by using 'RETURNING *'.
using var cmd = connection.CreateDmlCommand("DELETE FROM Singers WHERE FirstName = 'Lata' RETURNING SingerId, FullName");
var reader = await cmd.ExecuteReaderAsync();
var deletedSingerNames = new List<string>();
while (await reader.ReadAsync())
{
deletedSingerNames.Add(reader.GetFieldValue<string>("fullname"));
}
Console.WriteLine($"{deletedSingerNames.Count} row(s) deleted...");
return deletedSingerNames;
}
}Go
import (
"context"
"fmt"
"io"
"cloud.google.com/go/spanner"
"google.golang.org/api/iterator"
)
func pgDeleteUsingDMLReturning(w io.Writer, db string) error {
ctx := context.Background()
client, err := spanner.NewClient(ctx, db)
if err != nil {
return err
}
defer client.Close()
// Delete records from SINGERS table satisfying a
// particular condition and returns the SingerId
// and FullName column of the deleted records using
// 'RETURNING SingerId, FullName'.
// It is also possible to return all columns of all the
// deleted records by using 'RETURNING *'.
_, err = client.ReadWriteTransaction(ctx, func(ctx context.Context, txn *spanner.ReadWriteTransaction) error {
stmt := spanner.Statement{
SQL: `DELETE FROM Singers WHERE FirstName = 'Alice'
RETURNING SingerId, FullName`,
}
iter := txn.Query(ctx, stmt)
defer iter.Stop()
for {
row, err := iter.Next()
if err == iterator.Done {
break
}
if err != nil {
return err
}
var (
singerID int64
fullName string
)
if err := row.Columns(&singerID, &fullName); err != nil {
return err
}
fmt.Fprintf(w, "%d %s\n", singerID, fullName)
}
fmt.Fprintf(w, "%d record(s) deleted.\n", iter.RowCount)
return nil
})
return err
}
Java
import com.google.cloud.spanner.DatabaseClient;
import com.google.cloud.spanner.DatabaseId;
import com.google.cloud.spanner.ResultSet;
import com.google.cloud.spanner.Spanner;
import com.google.cloud.spanner.SpannerOptions;
import com.google.cloud.spanner.Statement;
public class PgDeleteUsingDmlReturningSample {
static void deleteUsingDmlReturningSample() {
// TODO(developer): Replace these variables before running the sample.
final String projectId = "my-project";
final String instanceId = "my-instance";
final String databaseId = "my-database";
deleteUsingDmlReturningSample(projectId, instanceId, databaseId);
}
static void deleteUsingDmlReturningSample(
String projectId, String instanceId, String databaseId) {
try (Spanner spanner =
SpannerOptions.newBuilder()
.setProjectId(projectId)
.build()
.getService()) {
final DatabaseClient dbClient =
spanner.getDatabaseClient(DatabaseId.of(projectId, instanceId, databaseId));
// Delete records from SINGERS table satisfying a
// particular condition and returns the SingerId
// and FullName column of the deleted records using
// ‘RETURNING SingerId, FullName’.
// It is also possible to return all columns of all the
// deleted records by using ‘RETURNING *’.
dbClient
.readWriteTransaction()
.run(
transaction -> {
String sql =
"DELETE FROM Singers WHERE FirstName = 'Alice' RETURNING SingerId, FullName";
// readWriteTransaction.executeQuery(..) API should be used for executing
// DML statements with RETURNING clause.
try (ResultSet resultSet = transaction.executeQuery(Statement.of(sql))) {
while (resultSet.next()) {
System.out.printf("%d %s\n", resultSet.getLong(0), resultSet.getString(1));
}
System.out.printf(
"Deleted row(s) count: %d\n", resultSet.getStats().getRowCountExact());
}
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,
});
function pgDeleteUsingDmlReturning(instanceId, databaseId) {
// 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 [rows, stats] = await transaction.run({
sql: 'DELETE FROM Singers WHERE SingerId = 18 RETURNING FullName',
});
const rowCount = Math.floor(stats[stats.rowCount]);
console.log(
`Successfully deleted ${rowCount} record from the Singers table.`
);
rows.forEach(row => {
console.log(row.toJSON().fullname);
});
await transaction.commit();
} catch (err) {
console.error('ERROR:', err);
} finally {
// Close the database when finished.
database.close();
}
});
}
pgDeleteUsingDmlReturning(instanceId, databaseId);PHP
use Google\Cloud\Spanner\SpannerClient;
/**
* Delete data from the given postgresql database using DML returning.
*
* @param string $instanceId The Spanner instance ID.
* @param string $databaseId The Spanner database ID.
*/
function pg_delete_dml_returning(string $instanceId, string $databaseId): void
{
$spanner = new SpannerClient();
$instance = $spanner->instance($instanceId);
$database = $instance->database($databaseId);
$transaction = $database->transaction();
// Delete records from SINGERS table satisfying a particular condition and
// returns the SingerId and FullName column of the deleted records using
// ‘RETURNING SingerId, FullName’. It is also possible to return all columns
// of all the deleted records by using ‘RETURNING *’.
$result = $transaction->execute(
"DELETE FROM Singers WHERE FirstName = 'Alice' "
. 'RETURNING SingerId, FullName',
);
foreach ($result->rows() as $row) {
printf(
'%d %s.' . PHP_EOL,
$row['singerid'],
$row['fullname']
);
}
printf(
'Deleted row(s) count: %d' . PHP_EOL,
$result->stats()['rowCountExact']
);
$transaction->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)
# Delete records from SINGERS table satisfying a
# particular condition and returns the SingerId
# and FullName column of the deleted records using
# 'RETURNING SingerId, FullName'.
# It is also possible to return all columns of all the
# deleted records by using 'RETURNING *'.
def delete_singers(transaction):
results = transaction.execute_sql(
"DELETE FROM Singers WHERE FirstName = 'David' "
"RETURNING SingerId, FullName"
)
for result in results:
print("SingerId: {}, FullName: {}".format(*result))
print("{} record(s) deleted.".format(results.stats.row_count_exact))
database.run_in_transaction(delete_singers)Rita
require "google/cloud/spanner"
##
# This is a snippet for showcasing how to use DML return feature with delete
# operation in PostgreSql.
#
# @param project_id [String] The ID of the Google Cloud project.
# @param instance_id [String] The ID of the spanner instance.
# @param database_id [String] The ID of the database.
#
def spanner_postgresql_delete_dml_returning project_id:, instance_id:, database_id:
spanner = Google::Cloud::Spanner.new project: project_id
client = spanner.client instance_id, database_id
client.transaction do |transaction|
# Delete records from SINGERS table satisfying a particular condition and
# returns the SingerId and FullName column of the deleted records using
# ‘RETURNING SingerId, FullName’.
# It is also possible to return all columns of all the deleted records
# by using ‘RETURNING *’.
results = transaction.execute_query "DELETE FROM singers WHERE firstname = 'Alice' RETURNING SingerId, FullName"
results.rows.each do |row|
puts "Deleted singer with SingerId: #{row[:singerid]}, FullName: #{row[:fullname]}"
end
puts "Deleted row(s) count: #{results.row_count}"
end
end
Lee datos escritos en la misma transacción
Los cambios que realices mediante las declaraciones DML serán visibles para las declaraciones posteriores de la misma transacción. No es lo mismo que usar mutaciones, cuyos cambios no son visibles hasta que la transacción se confirma.
Spanner verifica las restricciones después de cada declaración DML. Esto es diferente a usar mutaciones, en el que Spanner almacena en búfer las mutaciones del cliente hasta la confirmación y verifica las restricciones en el momento de la confirmación. Evaluar las restricciones después de cada declaración le permite a Spanner garantizar que los datos que muestra una declaración DML sean coherentes con el esquema.
En el ejemplo siguiente, se actualiza una fila en la tabla Singers, después, se ejecuta una declaración SELECT para mostrar los valores nuevos.
C++
void DmlWriteThenRead(google::cloud::spanner::Client client) {
namespace spanner = ::google::cloud::spanner;
using ::google::cloud::StatusOr;
auto commit_result = client.Commit(
[&client](spanner::Transaction txn) -> StatusOr<spanner::Mutations> {
auto insert = client.ExecuteDml(
txn, spanner::SqlStatement(
"INSERT INTO Singers (SingerId, FirstName, LastName)"
" VALUES (11, 'Timothy', 'Campbell')"));
if (!insert) return std::move(insert).status();
// Read newly inserted record.
spanner::SqlStatement select(
"SELECT FirstName, LastName FROM Singers where SingerId = 11");
using RowType = std::tuple<std::string, std::string>;
auto rows = client.ExecuteQuery(std::move(txn), std::move(select));
// Note: This mutator might be re-run, or its effects discarded, so
// changing non-transactional state (e.g., by producing output) is,
// in general, not something to be imitated.
for (auto const& row : spanner::StreamOf<RowType>(rows)) {
if (!row) return std::move(row).status();
std::cout << "FirstName: " << std::get<0>(*row) << "\t";
std::cout << "LastName: " << std::get<1>(*row) << "\n";
}
return spanner::Mutations{};
});
if (!commit_result) throw std::move(commit_result).status();
std::cout << "Write then read succeeded [spanner_dml_write_then_read]\n";
}C#
using Google.Cloud.Spanner.Data;
using System;
using System.Threading.Tasks;
public class WriteAndReadUsingDmlCoreAsyncSample
{
public async Task<int> WriteAndReadUsingDmlCoreAsync(string projectId, string instanceId, string databaseId)
{
string connectionString = $"Data Source=projects/{projectId}/instances/{instanceId}/databases/{databaseId}";
using var connection = new SpannerConnection(connectionString);
await connection.OpenAsync();
using var createDmlCmd = connection.CreateDmlCommand(@"INSERT Singers (SingerId, FirstName, LastName) VALUES (11, 'Timothy', 'Campbell')");
int rowCount = await createDmlCmd.ExecuteNonQueryAsync();
Console.WriteLine($"{rowCount} row(s) inserted...");
// Read newly inserted record.
using var createSelectCmd = connection.CreateSelectCommand(@"SELECT FirstName, LastName FROM Singers WHERE SingerId = 11");
using var reader = await createSelectCmd.ExecuteReaderAsync();
while (await reader.ReadAsync())
{
Console.WriteLine($"{reader.GetFieldValue<string>("FirstName")} {reader.GetFieldValue<string>("LastName")}");
}
return rowCount;
}
}Go
import (
"context"
"fmt"
"io"
"cloud.google.com/go/spanner"
"google.golang.org/api/iterator"
)
func writeAndReadUsingDML(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 {
// 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(transaction -> {
// 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";
// We use a try-with-resource block to automatically release resources held by
// ResultSet.
try (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(string $instanceId, string $databaseId): void
{
$spanner = new SpannerClient();
$instance = $spanner->instance($instanceId);
$database = $instance->database($databaseId);
$database->runTransaction(function (Transaction $t) {
$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 INTO 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)Rita
# 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
endObtén el plan de consultas
Puedes recuperar un plan de consultas con la consola de Google Cloud, las bibliotecas cliente y la herramienta de línea de comandos de gcloud.
Usa DML particionado
El DML particionado está diseñado con el fin de borrar y actualizar de forma masiva, en especial para la limpieza y el reabastecimiento periódico.
Ejecuta sentencias con Google Cloud CLI
Si deseas ejecutar una declaración DML particionada, usa el comando gcloud spanner databases execute-sql con la opción --enable-partitioned-dml. En el ejemplo siguiente, se actualizan las filas de la tabla Albums.
gcloud spanner databases execute-sql example-db \
--instance=test-instance --enable-partitioned-dml \
--sql='UPDATE Albums SET MarketingBudget = 0 WHERE MarketingBudget IS NULL'
Modifica datos con la biblioteca cliente
En el siguiente ejemplo de código, se actualiza la columna MarketingBudget de la tabla Albums.
C++
Usa la función ExecutePartitionedDml() para ejecutar una declaración DML particionada.
void DmlPartitionedUpdate(google::cloud::spanner::Client client) {
namespace spanner = ::google::cloud::spanner;
auto result = client.ExecutePartitionedDml(
spanner::SqlStatement("UPDATE Albums SET MarketingBudget = 100000"
" WHERE SingerId > 1"));
if (!result) throw std::move(result).status();
std::cout << "Updated at least " << result->row_count_lower_bound
<< " row(s) [spanner_dml_partitioned_update]\n";
}C#
Usa el método ExecutePartitionedUpdateAsync() para ejecutar una declaración DML particionada.
using Google.Cloud.Spanner.Data;
using System;
using System.Threading.Tasks;
public class UpdateUsingPartitionedDmlCoreAsyncSample
{
public async Task<long> UpdateUsingPartitionedDmlCoreAsync(string projectId, string instanceId, string databaseId)
{
string connectionString = $"Data Source=projects/{projectId}/instances/{instanceId}/databases/{databaseId}";
using var connection = new SpannerConnection(connectionString);
await connection.OpenAsync();
using var cmd = connection.CreateDmlCommand("UPDATE Albums SET MarketingBudget = 100000 WHERE SingerId > 1");
long rowCount = await cmd.ExecutePartitionedUpdateAsync();
Console.WriteLine($"{rowCount} row(s) updated...");
return rowCount;
}
}Go
Usa el método PartitionedUpdate() para ejecutar una declaración DML particionada.
import (
"context"
"fmt"
"io"
"cloud.google.com/go/spanner"
)
func updateUsingPartitionedDML(w io.Writer, db string) error {
ctx := context.Background()
client, err := spanner.NewClient(ctx, db)
if err != nil {
return err
}
defer client.Close()
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
Usa el método executePartitionedUpdate() para ejecutar una declaración 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
Usa el método runPartitionedUpdate() para ejecutar una declaración 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 ${rowCount} records.`);
} catch (err) {
console.error('ERROR:', err);
} finally {
// Close the database when finished.
database.close();
}PHP
Usa el método executePartitionedUpdate() para ejecutar una declaración DML particionada.
use Google\Cloud\Spanner\SpannerClient;
/**
* Updates sample data in the database by partition with a DML statement.
*
* This updates the `MarketingBudget` column which must be created before
* running this sample. You can add the column by running the `add_column`
* sample or by running this DDL statement against your database:
*
* ALTER TABLE Albums ADD COLUMN MarketingBudget INT64
*
* Example:
* ```
* update_data($instanceId, $databaseId);
* ```
*
* @param string $instanceId The Spanner instance ID.
* @param string $databaseId The Spanner database ID.
*/
function update_data_with_partitioned_dml(string $instanceId, string $databaseId): void
{
$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
Usa el método execute_partitioned_dml() para ejecutar una declaración 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))Rita
Usa el método execute_partitioned_update() para ejecutar una declaración 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."En el siguiente ejemplo de código, se borran las filas de la tabla Singers según la columna SingerId.
C++
void DmlPartitionedDelete(google::cloud::spanner::Client client) {
namespace spanner = ::google::cloud::spanner;
auto result = client.ExecutePartitionedDml(
spanner::SqlStatement("DELETE FROM Singers WHERE SingerId > 10"));
if (!result) throw std::move(result).status();
std::cout << "Deleted at least " << result->row_count_lower_bound
<< " row(s) [spanner_dml_partitioned_delete]\n";
}C#
using Google.Cloud.Spanner.Data;
using System;
using System.Threading.Tasks;
public class DeleteUsingPartitionedDmlCoreAsyncSample
{
public async Task<long> DeleteUsingPartitionedDmlCoreAsync(string projectId, string instanceId, string databaseId)
{
string connectionString = $"Data Source=projects/{projectId}/instances/{instanceId}/databases/{databaseId}";
using var connection = new SpannerConnection(connectionString);
await connection.OpenAsync();
using var cmd = connection.CreateDmlCommand("DELETE FROM Singers WHERE SingerId > 10");
long rowCount = await cmd.ExecutePartitionedUpdateAsync();
Console.WriteLine($"{rowCount} row(s) deleted...");
return rowCount;
}
}Go
import (
"context"
"fmt"
"io"
"cloud.google.com/go/spanner"
)
func deleteUsingPartitionedDML(w io.Writer, db string) error {
ctx := context.Background()
client, err := spanner.NewClient(ctx, db)
if err != nil {
return err
}
defer client.Close()
stmt := spanner.Statement{SQL: "DELETE FROM 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 FROM 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(string $instanceId, string $databaseId): void
{
$spanner = new SpannerClient();
$instance = $spanner->instance($instanceId);
$database = $instance->database($databaseId);
$rowCount = $database->executePartitionedUpdate(
'DELETE FROM 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 FROM Singers WHERE SingerId > 10")
print("{} record(s) deleted.".format(row_ct))Rita
# 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."Usar DML por lotes
Si necesitas evitar la latencia adicional que generan varias solicitudes en serie, usa DML por lotes para enviar varias declaraciones INSERT, UPDATE o DELETE en una sola transacción:
C++
Usa la función ExecuteBatchDml() para ejecutar una lista de declaraciones DML.
void DmlBatchUpdate(google::cloud::spanner::Client client) {
namespace spanner = ::google::cloud::spanner;
auto commit_result =
client.Commit([&client](spanner::Transaction const& txn)
-> google::cloud::StatusOr<spanner::Mutations> {
std::vector<spanner::SqlStatement> statements = {
spanner::SqlStatement("INSERT INTO Albums"
" (SingerId, AlbumId, AlbumTitle,"
" MarketingBudget)"
" VALUES (1, 3, 'Test Album Title', 10000)"),
spanner::SqlStatement("UPDATE Albums"
" SET MarketingBudget = MarketingBudget * 2"
" WHERE SingerId = 1 and AlbumId = 3")};
auto result = client.ExecuteBatchDml(txn, statements);
if (!result) return std::move(result).status();
// Note: This mutator might be re-run, or its effects discarded, so
// changing non-transactional state (e.g., by producing output) is,
// in general, not something to be imitated.
for (std::size_t i = 0; i < result->stats.size(); ++i) {
std::cout << result->stats[i].row_count << " rows affected"
<< " for the statement " << (i + 1) << ".\n";
}
// Batch operations may have partial failures, in which case
// ExecuteBatchDml returns with success, but the application should
// verify that all statements completed successfully
if (!result->status.ok()) return result->status;
return spanner::Mutations{};
});
if (!commit_result) throw std::move(commit_result).status();
std::cout << "Update was successful [spanner_dml_batch_update]\n";
}C#
Usa el método connection.CreateBatchDmlCommand() si deseas crear tu comando por lotes, usa el método Add para agregar declaraciones DML y ejecuta las instrucciones con el método ExecuteNonQueryAsync().
using Google.Cloud.Spanner.Data;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
public class UpdateUsingBatchDmlCoreAsyncSample
{
public async Task<int> UpdateUsingBatchDmlCoreAsync(string projectId, string instanceId, string databaseId)
{
string connectionString = $"Data Source=projects/{projectId}/instances/{instanceId}/databases/{databaseId}";
using var connection = new SpannerConnection(connectionString);
await connection.OpenAsync();
SpannerBatchCommand cmd = connection.CreateBatchDmlCommand();
cmd.Add("INSERT INTO Albums (SingerId, AlbumId, AlbumTitle, MarketingBudget) VALUES (1, 3, 'Test Album Title', 10000)");
cmd.Add("UPDATE Albums SET MarketingBudget = MarketingBudget * 2 WHERE SingerId = 1 and AlbumId = 3");
IEnumerable<long> affectedRows = await cmd.ExecuteNonQueryAsync();
Console.WriteLine($"Executed {affectedRows.Count()} " + "SQL statements using Batch DML.");
return affectedRows.Count();
}
}Go
Usa el método BatchUpdate() para ejecutar un arreglo de objetos Statement de DML.
import (
"context"
"fmt"
"io"
"cloud.google.com/go/spanner"
)
func updateUsingBatchDML(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 {
stmts := []spanner.Statement{
{SQL: `INSERT INTO Albums
(SingerId, AlbumId, AlbumTitle, MarketingBudget)
VALUES (1, 3, 'Test Album Title', 10000)`},
{SQL: `UPDATE Albums
SET MarketingBudget = MarketingBudget * 2
WHERE SingerId = 1 and AlbumId = 3`},
}
rowCounts, err := txn.BatchUpdate(ctx, stmts)
if err != nil {
return err
}
fmt.Fprintf(w, "Executed %d SQL statements using Batch DML.\n", len(rowCounts))
return nil
})
return err
}
Java
Usa el método transaction.batchUpdate() para ejecutar una ArrayList de varios objetos Statement de DML.
static void updateUsingBatchDml(DatabaseClient dbClient) {
dbClient
.readWriteTransaction()
.run(transaction -> {
List<Statement> stmts = new ArrayList<Statement>();
String sql =
"INSERT INTO Albums "
+ "(SingerId, AlbumId, AlbumTitle, MarketingBudget) "
+ "VALUES (1, 3, 'Test Album Title', 10000) ";
stmts.add(Statement.of(sql));
sql =
"UPDATE Albums "
+ "SET MarketingBudget = MarketingBudget * 2 "
+ "WHERE SingerId = 1 and AlbumId = 3";
stmts.add(Statement.of(sql));
long[] rowCounts;
try {
rowCounts = transaction.batchUpdate(stmts);
} catch (SpannerBatchUpdateException e) {
rowCounts = e.getUpdateCounts();
}
for (int i = 0; i < rowCounts.length; i++) {
System.out.printf("%d record updated by stmt %d.\n", rowCounts[i], i);
}
return null;
});
}Node.js
Usa transaction.batchUpdate() para ejecutar una lista de declaraciones 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);
const insert = {
sql: `INSERT INTO Albums (SingerId, AlbumId, AlbumTitle, MarketingBudget)
VALUES (1, 3, "Test Album Title", 10000)`,
};
const update = {
sql: `UPDATE Albums SET MarketingBudget = MarketingBudget * 2
WHERE SingerId = 1 and AlbumId = 3`,
};
const dmlStatements = [insert, update];
try {
await database.runTransactionAsync(async transaction => {
const [rowCounts] = await transaction.batchUpdate(dmlStatements);
await transaction.commit();
console.log(
`Successfully executed ${rowCounts.length} SQL statements using Batch DML.`
);
});
} catch (err) {
console.error('ERROR:', err);
throw err;
} finally {
// Close the database when finished.
database.close();
}PHP
Usa executeUpdateBatch() para crear una lista de declaraciones DML y, luego, usa commit() a fin de ejecutar las declaraciones.
use Google\Cloud\Spanner\SpannerClient;
use Google\Cloud\Spanner\Transaction;
/**
* Updates sample data in the database with Batch DML.
*
* This requires the `MarketingBudget` column which must be created before
* running this sample. You can add the column by running the `add_column`
* sample or by running this DDL statement against your database:
*
* ALTER TABLE Albums ADD COLUMN MarketingBudget INT64
*
* Example:
* ```
* update_data_with_batch_dml($instanceId, $databaseId);
* ```
*
* @param string $instanceId The Spanner instance ID.
* @param string $databaseId The Spanner database ID.
*/
function update_data_with_batch_dml(string $instanceId, string $databaseId): void
{
$spanner = new SpannerClient();
$instance = $spanner->instance($instanceId);
$database = $instance->database($databaseId);
$batchDmlResult = $database->runTransaction(function (Transaction $t) {
$result = $t->executeUpdateBatch([
[
'sql' => 'INSERT INTO Albums '
. '(SingerId, AlbumId, AlbumTitle, MarketingBudget) '
. "VALUES (1, 3, 'Test Album Title', 10000)"
],
[
'sql' => 'UPDATE Albums '
. 'SET MarketingBudget = MarketingBudget * 2 '
. 'WHERE SingerId = 1 and AlbumId = 3'
],
]);
$t->commit();
$rowCounts = count($result->rowCounts());
printf('Executed %s SQL statements using Batch DML.' . PHP_EOL,
$rowCounts);
});
}Python
Usa transaction.batch_update() para ejecutar varias strings de declaraciones DML.
from google.rpc.code_pb2 import OK
# 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)
insert_statement = (
"INSERT INTO Albums "
"(SingerId, AlbumId, AlbumTitle, MarketingBudget) "
"VALUES (1, 3, 'Test Album Title', 10000)"
)
update_statement = (
"UPDATE Albums "
"SET MarketingBudget = MarketingBudget * 2 "
"WHERE SingerId = 1 and AlbumId = 3"
)
def update_albums(transaction):
status, row_cts = transaction.batch_update([insert_statement, update_statement])
if status.code != OK:
# Do handling here.
# Note: the exception will still be raised when
# `commit` is called by `run_in_transaction`.
return
print("Executed {} SQL statements using Batch DML.".format(len(row_cts)))
database.run_in_transaction(update_albums)Rita
Usa transaction.batch_update para ejecutar varias strings de declaraciones 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_counts = nil
client.transaction do |transaction|
row_counts = transaction.batch_update do |b|
b.batch_update(
"INSERT INTO Albums " \
"(SingerId, AlbumId, AlbumTitle, MarketingBudget) " \
"VALUES (1, 3, 'Test Album Title', 10000)"
)
b.batch_update(
"UPDATE Albums " \
"SET MarketingBudget = MarketingBudget * 2 " \
"WHERE SingerId = 1 and AlbumId = 3"
)
end
end
statement_count = row_counts.count
puts "Executed #{statement_count} SQL statements using Batch DML."