Quickstart

Use a basic SELECT query.

Explore further

For detailed documentation that includes this code sample, see the following:

• Getting started with Spanner in C#
• Getting started with Spanner in Node.js
• Getting started with Spanner in PHP
• Getting started with Spanner in Python
• Getting started with Spanner in Ruby
• Spanner client libraries

Code sample

C++

To learn how to install and use the client library for Spanner, see Spanner client libraries.

To authenticate to Spanner, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

#include "google/cloud/spanner/client.h"
void Quickstart(std::string const& project_id, std::string const& instance_id,
                std::string const& database_id) {
  namespace spanner = ::google::cloud::spanner;

  auto database = spanner::Database(project_id, instance_id, database_id);
  auto connection = spanner::MakeConnection(database);
  auto client = spanner::Client(connection);

  auto rows =
      client.ExecuteQuery(spanner::SqlStatement("SELECT 'Hello World'"));
  using RowType = std::tuple<std::string>;
  for (auto& row : spanner::StreamOf<RowType>(rows)) {
    if (!row) throw std::move(row).status();
    std::cout << std::get<0>(*row) << "\n";
  }
}

C#

To learn how to install and use the client library for Spanner, see Spanner client libraries.

To authenticate to Spanner, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

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

namespace GoogleCloudSamples.Spanner
{
    public class QuickStart
    {
        static async Task MainAsync()
        {
            string projectId = "YOUR-PROJECT-ID";
            string instanceId = "my-instance";
            string databaseId = "my-database";
            string connectionString =
                $"Data Source=projects/{projectId}/instances/{instanceId}/"
                + $"databases/{databaseId}";
            // Create connection to Cloud Spanner.
            using (var connection = new SpannerConnection(connectionString))
            {
                // Execute a simple SQL statement.
                var cmd = connection.CreateSelectCommand(
                    @"SELECT ""Hello World"" as test");
                using (var reader = await cmd.ExecuteReaderAsync())
                {
                    while (await reader.ReadAsync())
                    {
                        Console.WriteLine(
                            reader.GetFieldValue<string>("test"));
                    }
                }
            }
        }
        public static void Main(string[] args)
        {
            MainAsync().Wait();
        }
    }
}

Go

To learn how to install and use the client library for Spanner, see Spanner client libraries.

To authenticate to Spanner, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

// Sample spanner_quickstart is a basic program that uses Cloud Spanner.
package main

import (
	"context"
	"fmt"
	"log"

	"cloud.google.com/go/spanner"
	"google.golang.org/api/iterator"
)

func main() {
	ctx := context.Background()

	// This database must exist.
	databaseName := "projects/your-project-id/instances/your-instance-id/databases/your-database-id"

	client, err := spanner.NewClient(ctx, databaseName)
	if err != nil {
		log.Fatalf("Failed to create client %v", err)
	}
	defer client.Close()

	stmt := spanner.Statement{SQL: "SELECT 1"}
	iter := client.Single().Query(ctx, stmt)
	defer iter.Stop()

	for {
		row, err := iter.Next()
		if err == iterator.Done {
			fmt.Println("Done")
			return
		}
		if err != nil {
			log.Fatalf("Query failed with %v", err)
		}

		var i int64
		if row.Columns(&i) != nil {
			log.Fatalf("Failed to parse row %v", err)
		}
		fmt.Printf("Got value %v\n", i)
	}
}

Java

To learn how to install and use the client library for Spanner, see Spanner client libraries.

To authenticate to Spanner, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

// Imports the Google Cloud client library
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;

/**
 * A quick start code for Cloud Spanner. It demonstrates how to setup the Cloud Spanner client and
 * execute a simple query using it against an existing database.
 */
public class QuickstartSample {
  public static void main(String... args) throws Exception {

    if (args.length != 2) {
      System.err.println("Usage: QuickStartSample <instance_id> <database_id>");
      return;
    }
    // Instantiates a client
    SpannerOptions options = SpannerOptions.newBuilder().build();
    Spanner spanner = options.getService();

    // Name of your instance & database.
    String instanceId = args[0];
    String databaseId = args[1];
    try {
      // Creates a database client
      DatabaseClient dbClient =
          spanner.getDatabaseClient(DatabaseId.of(options.getProjectId(), instanceId, databaseId));
      // Queries the database
      ResultSet resultSet = dbClient.singleUse().executeQuery(Statement.of("SELECT 1"));

      System.out.println("\n\nResults:");
      // Prints the results
      while (resultSet.next()) {
        System.out.printf("%d\n\n", resultSet.getLong(0));
      }
    } finally {
      // Closes the client which will free up the resources used
      spanner.close();
    }
  }
}

Node.js

To learn how to install and use the client library for Spanner, see Spanner client libraries.

To authenticate to Spanner, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

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

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

// Gets a reference to a Cloud Spanner instance and database
const instance = spanner.instance(instanceId);
const database = instance.database(databaseId);

// The query to execute
const query = {
  sql: 'SELECT 1',
};

// Execute a simple SQL statement
const [rows] = await database.run(query);
console.log(`Query: ${rows.length} found.`);
rows.forEach(row => console.log(row));

PHP

To learn how to install and use the client library for Spanner, see Spanner client libraries.

To authenticate to Spanner, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

# Includes the autoloader for libraries installed with composer
require __DIR__ . '/vendor/autoload.php';

# Imports the Google Cloud client library
use Google\Cloud\Spanner\SpannerClient;

# Your Google Cloud Platform project ID
$projectId = 'YOUR_PROJECT_ID';

# Instantiates a client
$spanner = new SpannerClient([
    'projectId' => $projectId
]);

# Your Cloud Spanner instance ID.
$instanceId = 'your-instance-id';

# Get a Cloud Spanner instance by ID.
$instance = $spanner->instance($instanceId);

# Your Cloud Spanner database ID.
$databaseId = 'your-database-id';

# Get a Cloud Spanner database by ID.
$database = $instance->database($databaseId);

# Execute a simple SQL statement.
$results = $database->execute('SELECT "Hello World" as test');

foreach ($results as $row) {
    print($row['test'] . PHP_EOL);
}

Python

To learn how to install and use the client library for Spanner, see Spanner client libraries.

To authenticate to Spanner, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

# Imports the Google Cloud Client Library.
from google.cloud import spanner

# Your Cloud Spanner instance ID.
# instance_id = "my-instance-id"
#
# Your Cloud Spanner database ID.
# database_id = "my-database-id"
# Instantiate a client.
spanner_client = spanner.Client()

# Get a Cloud Spanner instance by ID.
instance = spanner_client.instance(instance_id)

# Get a Cloud Spanner database by ID.
database = instance.database(database_id)

# Execute a simple SQL statement.
with database.snapshot() as snapshot:
    results = snapshot.execute_sql("SELECT 1")

    for row in results:
        print(row)

Ruby

To learn how to install and use the client library for Spanner, see Spanner client libraries.

To authenticate to Spanner, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

# Imports the Google Cloud client library
require "google/cloud/spanner"

# Your Google Cloud Platform project ID
project_id = "YOUR_PROJECT_ID"

# Instantiates a client
spanner = Google::Cloud::Spanner.new project: project_id

# Your Cloud Spanner instance ID
instance_id = "my-instance"

# Your Cloud Spanner database ID
database_id = "my-database"

# Gets a reference to a Cloud Spanner instance database
database_client = spanner.client instance_id, database_id

# Execute a simple SQL statement
results = database_client.execute_query "SELECT 1"
results.rows.each do |row|
  puts row
end

What's next

To search and filter code samples for other Google Cloud products, see the Google Cloud sample browser.