Spanner Graph 설정 및 쿼리

def create_database_with_property_graph(instance_id, database_id):
    """Creates a database, tables and a property graph for sample data."""
    from google.cloud.spanner_admin_database_v1.types import spanner_database_admin

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

    request = spanner_database_admin.CreateDatabaseRequest(
        parent=database_admin_api.instance_path(spanner_client.project, instance_id),
        create_statement=f"CREATE DATABASE `{database_id}`",
        extra_statements=[
            """CREATE TABLE Person (
            id               INT64 NOT NULL,
            name             STRING(MAX),
            birthday         TIMESTAMP,
            country          STRING(MAX),
            city             STRING(MAX),
        ) PRIMARY KEY (id)""",
            """CREATE TABLE Account (
            id               INT64 NOT NULL,
            create_time      TIMESTAMP,
            is_blocked       BOOL,
            nick_name        STRING(MAX),
        ) PRIMARY KEY (id)""",
            """CREATE TABLE PersonOwnAccount (
            id               INT64 NOT NULL,
            account_id       INT64 NOT NULL,
            create_time      TIMESTAMP,
            FOREIGN KEY (account_id)
                REFERENCES Account (id)
        ) PRIMARY KEY (id, account_id),
        INTERLEAVE IN PARENT Person ON DELETE CASCADE""",
            """CREATE TABLE AccountTransferAccount (
            id               INT64 NOT NULL,
            to_id            INT64 NOT NULL,
            amount           FLOAT64,
            create_time      TIMESTAMP NOT NULL,
            order_number     STRING(MAX),
            FOREIGN KEY (to_id) REFERENCES Account (id)
        ) PRIMARY KEY (id, to_id, create_time),
        INTERLEAVE IN PARENT Account ON DELETE CASCADE""",
            """CREATE OR REPLACE PROPERTY GRAPH FinGraph
            NODE TABLES (Account, Person)
            EDGE TABLES (
                PersonOwnAccount
                    SOURCE KEY(id) REFERENCES Person(id)
                    DESTINATION KEY(account_id) REFERENCES Account(id)
                    LABEL Owns,
                AccountTransferAccount
                    SOURCE KEY(id) REFERENCES Account(id)
                    DESTINATION KEY(to_id) REFERENCES Account(id)
                    LABEL Transfers)""",
        ],
    )

    operation = database_admin_api.create_database(request=request)

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

    print(
        "Created database {} on instance {}".format(
            database.name,
            database_admin_api.instance_path(spanner_client.project, instance_id),
        )
    )

static void createDatabaseWithPropertyGraph(
    DatabaseAdminClient dbAdminClient, InstanceName instanceName, String databaseId) {
  CreateDatabaseRequest createDatabaseRequest =
      CreateDatabaseRequest.newBuilder()
          .setCreateStatement("CREATE DATABASE `" + databaseId + "`")
          .setParent(instanceName.toString())
          .addAllExtraStatements(
              Arrays.asList(
                  "CREATE TABLE Person ("
                      + "  id               INT64 NOT NULL,"
                      + "  name             STRING(MAX),"
                      + "  birthday         TIMESTAMP,"
                      + "  country          STRING(MAX),"
                      + "  city             STRING(MAX),"
                      + ") PRIMARY KEY (id)",
                  "CREATE TABLE Account ("
                      + "  id               INT64 NOT NULL,"
                      + "  create_time      TIMESTAMP,"
                      + "  is_blocked       BOOL,"
                      + "  nick_name        STRING(MAX),"
                      + ") PRIMARY KEY (id)",
                  "CREATE TABLE PersonOwnAccount ("
                      + "  id               INT64 NOT NULL,"
                      + "  account_id       INT64 NOT NULL,"
                      + "  create_time      TIMESTAMP,"
                      + "  FOREIGN KEY (account_id)"
                      + "  REFERENCES Account (id)"
                      + ") PRIMARY KEY (id, account_id),"
                      + "INTERLEAVE IN PARENT Person ON DELETE CASCADE",
                  "CREATE TABLE AccountTransferAccount ("
                      + "  id               INT64 NOT NULL,"
                      + "  to_id            INT64 NOT NULL,"
                      + "  amount           FLOAT64,"
                      + "  create_time      TIMESTAMP NOT NULL,"
                      + "  order_number     STRING(MAX),"
                      + "  FOREIGN KEY (to_id) REFERENCES Account (id)"
                      + ") PRIMARY KEY (id, to_id, create_time),"
                      + "INTERLEAVE IN PARENT Account ON DELETE CASCADE",
                  "CREATE OR REPLACE PROPERTY GRAPH FinGraph "
                      + "NODE TABLES (Account, Person)"
                      + "EDGE TABLES ("
                      + "  PersonOwnAccount"
                      + "    SOURCE KEY(id) REFERENCES Person(id)"
                      + "    DESTINATION KEY(account_id) REFERENCES Account(id)"
                      + "    LABEL Owns,"
                      + "  AccountTransferAccount"
                      + "    SOURCE KEY(id) REFERENCES Account(id)"
                      + "    DESTINATION KEY(to_id) REFERENCES Account(id)"
                      + "    LABEL Transfers)"))
          .build();
  try {
    // Initiate the request which returns an OperationFuture.
    com.google.spanner.admin.database.v1.Database db =
        dbAdminClient.createDatabaseAsync(createDatabaseRequest).get();
    System.out.println("Created database [" + db.getName() + "]");
  } catch (ExecutionException e) {
    // If the operation failed during execution, expose the cause.
    System.out.println("Encountered exception" + e.getCause());
    throw (SpannerException) e.getCause();
  } catch (InterruptedException e) {
    // Throw when a thread is waiting, sleeping, or otherwise occupied,
    // and the thread is interrupted, either before or during the activity.
    throw SpannerExceptionFactory.propagateInterrupt(e);
  }
}

import (
	"context"
	"fmt"
	"io"
	"regexp"

	database "cloud.google.com/go/spanner/admin/database/apiv1"
	adminpb "google.golang.org/genproto/googleapis/spanner/admin/database/v1"
)

func createDatabaseWithPropertyGraph(ctx context.Context, w io.Writer, dbId string) error {
	// dbId is of the form:
	// 	projects/YOUR_PROJECT_ID/instances/YOUR_INSTANCE_ID/databases/YOUR_DATABASE_NAME
	matches := regexp.MustCompile("^(.*)/databases/(.*)$").FindStringSubmatch(dbId)
	if matches == nil || len(matches) != 3 {
		return fmt.Errorf("Invalid database id %s", dbId)
	}

	adminClient, err := database.NewDatabaseAdminClient(ctx)
	if err != nil {
		return err
	}
	defer adminClient.Close()

	var instance = matches[1]
	var dbName = matches[2]

	// The schema defintion for a database with a property graph comprises table
	// definitions one or more `CREATE PROPERTY GRAPH` statements to define the
	// property graph(s).
	//
	// Here, tables are created for 'Person's and 'Account's. The property graph
	// definition says that these entities form nodes in the graph. Similarly,
	// there are 'PersonOwnAccount' and 'AccountTransferAccount' relationship
	// tables defined. The property graph definition maps these to edges in the graph.
	var schema_statements = []string{
		`CREATE TABLE Person (
			id               INT64 NOT NULL,
			name             STRING(MAX),
			birthday         TIMESTAMP,
			country          STRING(MAX),
			city             STRING(MAX),
		) PRIMARY KEY (id)`,
		`CREATE TABLE Account (
			id               INT64 NOT NULL,
			create_time      TIMESTAMP,
			is_blocked       BOOL,
			nick_name        STRING(MAX),
		) PRIMARY KEY (id)`,
		`CREATE TABLE PersonOwnAccount (
			id               INT64 NOT NULL,
			account_id       INT64 NOT NULL,
			create_time      TIMESTAMP,
			FOREIGN KEY (account_id)
				REFERENCES Account (id)
		) PRIMARY KEY (id, account_id),
		INTERLEAVE IN PARENT Person ON DELETE CASCADE`,
		`CREATE TABLE AccountTransferAccount (
			id               INT64 NOT NULL,
			to_id            INT64 NOT NULL,
			amount           FLOAT64,
			create_time      TIMESTAMP NOT NULL,
			order_number     STRING(MAX),
			FOREIGN KEY (to_id) REFERENCES Account (id)
		) PRIMARY KEY (id, to_id, create_time),
		INTERLEAVE IN PARENT Account ON DELETE CASCADE`,
		`CREATE OR REPLACE PROPERTY GRAPH FinGraph
			NODE TABLES (Account, Person)
			EDGE TABLES (
				PersonOwnAccount
					SOURCE KEY(id) REFERENCES Person(id)
					DESTINATION KEY(account_id) REFERENCES Account(id)
					LABEL Owns,
				AccountTransferAccount
					SOURCE KEY(id) REFERENCES Account(id)
					DESTINATION KEY(to_id) REFERENCES Account(id)
					LABEL Transfers)`,
	}

	op, err := adminClient.CreateDatabase(ctx, &adminpb.CreateDatabaseRequest{
		Parent:          instance,
		CreateStatement: "CREATE DATABASE `" + dbName + "`",
		ExtraStatements: schema_statements,
	})
	if err != nil {
		return err
	}
	if _, err := op.Wait(ctx); err != nil {
		return err
	}
	fmt.Fprintf(w, "Created database [%s]\n", dbId)
	return nil
}

void CreateDatabaseWithPropertyGraph(
    google::cloud::spanner_admin::DatabaseAdminClient client,
    std::string const& project_id, std::string const& instance_id,
    std::string const& database_id) {
  google::cloud::spanner::Database database(project_id, instance_id,
                                            database_id);
  google::spanner::admin::database::v1::CreateDatabaseRequest request;
  request.set_parent(database.instance().FullName());
  request.set_create_statement("CREATE DATABASE `" + database.database_id() +
                               "`");
  request.add_extra_statements(R"""(
    CREATE TABLE Person (
      id               INT64 NOT NULL,
      name             STRING(MAX),
      birthday         TIMESTAMP,
      country          STRING(MAX),
      city             STRING(MAX),
    ) PRIMARY KEY (id))""");
  request.add_extra_statements(R"""(
    CREATE TABLE Account (
      id               INT64 NOT NULL,
      create_time      TIMESTAMP,
      is_blocked       BOOL,
      nick_name        STRING(MAX),
    ) PRIMARY KEY (id))""");
  request.add_extra_statements(R"""(
    CREATE TABLE PersonOwnAccount (
      id               INT64 NOT NULL,
      account_id       INT64 NOT NULL,
      create_time      TIMESTAMP,
      FOREIGN KEY (account_id)
      REFERENCES Account (id)
    ) PRIMARY KEY (id, account_id),
      INTERLEAVE IN PARENT Person ON DELETE CASCADE)""");
  request.add_extra_statements(R"""(
    CREATE TABLE AccountTransferAccount (
      id               INT64 NOT NULL,
      to_id            INT64 NOT NULL,
      amount           FLOAT64,
      create_time      TIMESTAMP NOT NULL,
      order_number     STRING(MAX),
      FOREIGN KEY (to_id) REFERENCES Account (id)
    ) PRIMARY KEY (id, to_id, create_time),
      INTERLEAVE IN PARENT Account ON DELETE CASCADE)""");
  request.add_extra_statements(R"""(
    CREATE OR REPLACE PROPERTY GRAPH FinGraph
      NODE TABLES (Account, Person)
      EDGE TABLES (
        PersonOwnAccount
          SOURCE KEY(id) REFERENCES Person(id)
          DESTINATION KEY(account_id) REFERENCES Account(id)
          LABEL Owns,
        AccountTransferAccount
          SOURCE KEY(id) REFERENCES Account(id)
          DESTINATION KEY(to_id) REFERENCES Account(id)
          LABEL Transfers))""");
  auto db = client.CreateDatabase(request).get();
  if (!db) throw std::move(db).status();
  std::cout << "Database " << db->name() << " created with property graph.\n";
}

def insert_data(instance_id, database_id):
    """Inserts sample data into the given database.

    The database and tables must already exist and can be created using
    `create_database_with_property_graph`.
    """
    spanner_client = spanner.Client()
    instance = spanner_client.instance(instance_id)
    database = instance.database(database_id)

    with database.batch() as batch:
        batch.insert(
            table="Account",
            columns=("id", "create_time", "is_blocked", "nick_name"),
            values=[
                (7, "2020-01-10T06:22:20.12Z", False, "Vacation Fund"),
                (16, "2020-01-27T17:55:09.12Z", True, "Vacation Fund"),
                (20, "2020-02-18T05:44:20.12Z", False, "Rainy Day Fund"),
            ],
        )

        batch.insert(
            table="Person",
            columns=("id", "name", "birthday", "country", "city"),
            values=[
                (1, "Alex", "1991-12-21T00:00:00.12Z", "Australia", " Adelaide"),
                (2, "Dana", "1980-10-31T00:00:00.12Z", "Czech_Republic", "Moravia"),
                (3, "Lee", "1986-12-07T00:00:00.12Z", "India", "Kollam"),
            ],
        )

        batch.insert(
            table="AccountTransferAccount",
            columns=("id", "to_id", "amount", "create_time", "order_number"),
            values=[
                (7, 16, 300.0, "2020-08-29T15:28:58.12Z", "304330008004315"),
                (7, 16, 100.0, "2020-10-04T16:55:05.12Z", "304120005529714"),
                (16, 20, 300.0, "2020-09-25T02:36:14.12Z", "103650009791820"),
                (20, 7, 500.0, "2020-10-04T16:55:05.12Z", "304120005529714"),
                (20, 16, 200.0, "2020-10-17T03:59:40.12Z", "302290001255747"),
            ],
        )

        batch.insert(
            table="PersonOwnAccount",
            columns=("id", "account_id", "create_time"),
            values=[
                (1, 7, "2020-01-10T06:22:20.12Z"),
                (2, 20, "2020-01-27T17:55:09.12Z"),
                (3, 16, "2020-02-18T05:44:20.12Z"),
            ],
        )

    print("Inserted data.")

/** Class to contain sample Person data. */
static class Person {

  final long id;
  final String name;
  final Timestamp birthday;
  final String country;
  final String city;

  Person(long id, String name, Timestamp birthday, String country, String city) {
    this.id = id;
    this.name = name;
    this.birthday = birthday;
    this.country = country;
    this.city = city;
  }
}

/** Class to contain sample Account data. */
static class Account {

  final long id;
  final Timestamp createTime;
  final boolean isBlocked;
  final String nickName;

  Account(long id, Timestamp createTime, boolean isBlocked, String nickName) {
    this.id = id;
    this.createTime = createTime;
    this.isBlocked = isBlocked;
    this.nickName = nickName;
  }
}

/** Class to contain sample Transfer data. */
static class Transfer {

  final long id;
  final long toId;
  final double amount;
  final Timestamp createTime;
  final String orderNumber;

  Transfer(long id, long toId, double amount, Timestamp createTime, String orderNumber) {
    this.id = id;
    this.toId = toId;
    this.amount = amount;
    this.createTime = createTime;
    this.orderNumber = orderNumber;
  }
}

/** Class to contain sample Ownership data. */
static class Own {

  final long id;
  final long accountId;
  final Timestamp createTime;

  Own(long id, long accountId, Timestamp createTime) {
    this.id = id;
    this.accountId = accountId;
    this.createTime = createTime;
  }
}

static final List<Account> ACCOUNTS =
    Arrays.asList(
        new Account(
            7, Timestamp.parseTimestamp("2020-01-10T06:22:20.12Z"), false, "Vacation Fund"),
        new Account(
            16, Timestamp.parseTimestamp("2020-01-27T17:55:09.12Z"), true, "Vacation Fund"),
        new Account(
            20, Timestamp.parseTimestamp("2020-02-18T05:44:20.12Z"), false, "Rainy Day Fund"));

static final List<Person> PERSONS =
    Arrays.asList(
        new Person(
            1,
            "Alex",
            Timestamp.parseTimestamp("1991-12-21T00:00:00.12Z"),
            "Australia",
            " Adelaide"),
        new Person(
            2,
            "Dana",
            Timestamp.parseTimestamp("1980-10-31T00:00:00.12Z"),
            "Czech_Republic",
            "Moravia"),
        new Person(
            3, "Lee", Timestamp.parseTimestamp("1986-12-07T00:00:00.12Z"), "India", "Kollam"));

static final List<Transfer> TRANSFERS =
    Arrays.asList(
        new Transfer(
            7, 16, 300.0, Timestamp.parseTimestamp("2020-08-29T15:28:58.12Z"), "304330008004315"),
        new Transfer(
            7, 16, 100.0, Timestamp.parseTimestamp("2020-10-04T16:55:05.12Z"), "304120005529714"),
        new Transfer(
            16,
            20,
            300.0,
            Timestamp.parseTimestamp("2020-09-25T02:36:14.12Z"),
            "103650009791820"),
        new Transfer(
            20, 7, 500.0, Timestamp.parseTimestamp("2020-10-04T16:55:05.12Z"), "304120005529714"),
        new Transfer(
            20,
            16,
            200.0,
            Timestamp.parseTimestamp("2020-10-17T03:59:40.12Z"),
            "302290001255747"));

static final List<Own> OWNERSHIPS =
    Arrays.asList(
        new Own(1, 7, Timestamp.parseTimestamp("2020-01-10T06:22:20.12Z")),
        new Own(2, 20, Timestamp.parseTimestamp("2020-01-27T17:55:09.12Z")),
        new Own(3, 16, Timestamp.parseTimestamp("2020-02-18T05:44:20.12Z")));

static void insertData(DatabaseClient dbClient) {
  List<Mutation> mutations = new ArrayList<>();
  for (Account account : ACCOUNTS) {
    mutations.add(
        Mutation.newInsertBuilder("Account")
            .set("id")
            .to(account.id)
            .set("create_time")
            .to(account.createTime)
            .set("is_blocked")
            .to(account.isBlocked)
            .set("nick_name")
            .to(account.nickName)
            .build());
  }
  for (Person person : PERSONS) {
    mutations.add(
        Mutation.newInsertBuilder("Person")
            .set("id")
            .to(person.id)
            .set("name")
            .to(person.name)
            .set("birthday")
            .to(person.birthday)
            .set("country")
            .to(person.country)
            .set("city")
            .to(person.city)
            .build());
  }
  for (Transfer transfer : TRANSFERS) {
    mutations.add(
        Mutation.newInsertBuilder("AccountTransferAccount")
            .set("id")
            .to(transfer.id)
            .set("to_id")
            .to(transfer.toId)
            .set("amount")
            .to(transfer.amount)
            .set("create_time")
            .to(transfer.createTime)
            .set("order_number")
            .to(transfer.orderNumber)
            .build());
  }
  for (Own own : OWNERSHIPS) {
    mutations.add(
        Mutation.newInsertBuilder("PersonOwnAccount")
            .set("id")
            .to(own.id)
            .set("account_id")
            .to(own.accountId)
            .set("create_time")
            .to(own.createTime)
            .build());
  }

  dbClient.write(mutations);
}

import (
	"context"
	"io"
	"time"

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

func parseTime(rfc3339Time string) time.Time {
	t, _ := time.Parse(time.RFC3339, rfc3339Time)
	return t
}

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

	// Values are inserted into the node and edge tables corresponding to
	// using Spanner 'Insert' mutations.
	// The tables and columns comply with the schema defined for the
	// property graph 'FinGraph', comprising 'Person' and 'Account' nodes,
	// and 'PersonOwnAccount' and 'AccountTransferAccount' edges.
	personColumns := []string{"id", "name", "birthday", "country", "city"}
	accountColumns := []string{"id", "create_time", "is_blocked", "nick_name"}
	ownColumns := []string{"id", "account_id", "create_time"}
	transferColumns := []string{"id", "to_id", "amount", "create_time", "order_number"}
	m := []*spanner.Mutation{
		spanner.Insert("Account", accountColumns,
			[]interface{}{7, parseTime("2020-01-10T06:22:20.12Z"), false, "Vacation Fund"}),
		spanner.Insert("Account", accountColumns,
			[]interface{}{16, parseTime("2020-01-27T17:55:09.12Z"), true, "Vacation Fund"}),
		spanner.Insert("Account", accountColumns,
			[]interface{}{20, parseTime("2020-02-18T05:44:20.12Z"), false, "Rainy Day Fund"}),
		spanner.Insert("Person", personColumns,
			[]interface{}{1, "Alex", parseTime("1991-12-21T00:00:00.12Z"), "Australia", " Adelaide"}),
		spanner.Insert("Person", personColumns,
			[]interface{}{2, "Dana", parseTime("1980-10-31T00:00:00.12Z"), "Czech_Republic", "Moravia"}),
		spanner.Insert("Person", personColumns,
			[]interface{}{3, "Lee", parseTime("1986-12-07T00:00:00.12Z"), "India", "Kollam"}),
		spanner.Insert("AccountTransferAccount", transferColumns,
			[]interface{}{7, 16, 300.0, parseTime("2020-08-29T15:28:58.12Z"), "304330008004315"}),
		spanner.Insert("AccountTransferAccount", transferColumns,
			[]interface{}{7, 16, 100.0, parseTime("2020-10-04T16:55:05.12Z"), "304120005529714"}),
		spanner.Insert("AccountTransferAccount", transferColumns,
			[]interface{}{16, 20, 300.0, parseTime("2020-09-25T02:36:14.12Z"), "103650009791820"}),
		spanner.Insert("AccountTransferAccount", transferColumns,
			[]interface{}{20, 7, 500.0, parseTime("2020-10-04T16:55:05.12Z"), "304120005529714"}),
		spanner.Insert("AccountTransferAccount", transferColumns,
			[]interface{}{20, 16, 200.0, parseTime("2020-10-17T03:59:40.12Z"), "302290001255747"}),
		spanner.Insert("PersonOwnAccount", ownColumns,
			[]interface{}{1, 7, parseTime("2020-01-10T06:22:20.12Z")}),
		spanner.Insert("PersonOwnAccount", ownColumns,
			[]interface{}{2, 20, parseTime("2020-01-27T17:55:09.12Z")}),
		spanner.Insert("PersonOwnAccount", ownColumns,
			[]interface{}{3, 16, parseTime("2020-02-18T05:44:20.12Z")}),
	}
	_, err = client.Apply(ctx, m)
	return err
}

void InsertData(google::cloud::spanner::Client client) {
  namespace spanner = ::google::cloud::spanner;

  auto insert_accounts =
      spanner::InsertMutationBuilder(
          "Account", {"id", "create_time", "is_blocked", "nick_name"})
          .EmplaceRow(7, spanner::Value("2020-01-10T06:22:20.12Z"), false,
                      "Vacation Fund")
          .EmplaceRow(16, spanner::Value("2020-01-27T17:55:09.12Z"), true,
                      "Vacation Fund")
          .EmplaceRow(20, spanner::Value("2020-02-18T05:44:20.12Z"), false,
                      "Rainy Day Fund")
          .Build();

  auto insert_persons =
      spanner::InsertMutationBuilder(
          "Person", {"id", "name", "birthday", "country", "city"})
          .EmplaceRow(1, "Alex", spanner::Value("1991-12-21T00:00:00.12Z"),
                      "Australia", "Adelaide")
          .EmplaceRow(2, "Dana", spanner::Value("1980-10-31T00:00:00.12Z"),
                      "Czech_Republic", "Moravia")
          .EmplaceRow(3, "Lee", spanner::Value("1986-12-07T00:00:00.12Z"),
                      "India", "Kollam")
          .Build();

  auto insert_transfers =
      spanner::InsertMutationBuilder(
          "AccountTransferAccount",
          {"id", "to_id", "amount", "create_time", "order_number"})
          .EmplaceRow(7, 16, 300.0, spanner::Value("2020-08-29T15:28:58.12Z"),
                      "304330008004315")
          .EmplaceRow(7, 16, 100.0, spanner::Value("2020-10-04T16:55:05.12Z"),
                      "304120005529714")
          .EmplaceRow(16, 20, 300.0, spanner::Value("2020-09-25T02:36:14.12Z"),
                      "103650009791820")
          .EmplaceRow(20, 7, 500.0, spanner::Value("2020-10-04T16:55:05.12Z"),
                      "304120005529714")
          .EmplaceRow(20, 16, 200.0, spanner::Value("2020-10-17T03:59:40.12Z"),
                      "302290001255747")
          .Build();

  auto insert_ownerships =
      spanner::InsertMutationBuilder("PersonOwnAccount",
                                     {"id", "account_id", "create_time"})
          .EmplaceRow(1, 7, spanner::Value("2020-01-10T06:22:20.12Z"))
          .EmplaceRow(2, 20, spanner::Value("2020-01-27T17:55:09.12Z"))
          .EmplaceRow(3, 16, spanner::Value("2020-02-18T05:44:20.12Z"))
          .Build();

  auto commit_result = client.Commit(spanner::Mutations{
      insert_accounts, insert_persons, insert_transfers, insert_ownerships});
  if (!commit_result) throw std::move(commit_result).status();
  std::cout << "Insert was successful [spanner_insert_graph_data]\n";
}

def query_data(instance_id, database_id):
    """Queries sample data from the database using GQL."""
    spanner_client = spanner.Client()
    instance = spanner_client.instance(instance_id)
    database = instance.database(database_id)

    with database.snapshot() as snapshot:
        results = snapshot.execute_sql(
            """Graph FinGraph
            MATCH (a:Person)-[o:Owns]->()-[t:Transfers]->()<-[p:Owns]-(b:Person)
            RETURN a.name AS sender, b.name AS receiver, t.amount, t.create_time AS transfer_at"""
        )

        for row in results:
            print("sender: {}, receiver: {}, amount: {}, transfer_at: {}".format(*row))

static void query(DatabaseClient dbClient) {
  try (ResultSet resultSet =
      dbClient
          .singleUse() // Execute a single query against Cloud Spanner.
          .executeQuery(
              Statement.of(
                  "Graph FinGraph MATCH"
                      + " (a:Person)-[o:Owns]->()-[t:Transfers]->()<-[p:Owns]-(b:Person)RETURN"
                      + " a.name AS sender, b.name AS receiver, t.amount, t.create_time AS"
                      + " transfer_at"))) {
    while (resultSet.next()) {
      System.out.printf(
          "%s %s %f %s\n",
          resultSet.getString(0),
          resultSet.getString(1),
          resultSet.getDouble(2),
          resultSet.getTimestamp(3));
    }
  }
}

import (
	"context"
	"fmt"
	"io"
	"time"

	"cloud.google.com/go/spanner"

	"google.golang.org/api/iterator"
)

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

	// Execute a Spanner query statement comprising a graph query. Graph queries
	// are characterized by 'MATCH' statements describing node and edge
	// patterns.
	//
	// This statement finds entities ('Account's) owned by all 'Person's 'b' to
	// which transfers have been made by entities ('Account's) owned by any
	// 'Person' 'a' in the graph called 'FinGraph'. It then returns the names of
	// all such 'Person's 'a' and 'b', and the amount and time of the transfer.
	stmt := spanner.Statement{SQL: `Graph FinGraph 
		 MATCH (a:Person)-[o:Owns]->()-[t:Transfers]->()<-[p:Owns]-(b:Person)
		 RETURN a.name AS sender, b.name AS receiver, t.amount, t.create_time AS transfer_at`}
	iter := client.Single().Query(ctx, stmt)
	defer iter.Stop()

	// The results are returned in tabular form. Iterate over the
	// result rows and print them.
	for {
		row, err := iter.Next()
		if err == iterator.Done {
			return nil
		}
		if err != nil {
			return err
		}
		var sender, receiver string
		var amount float64
		var transfer_at time.Time
		if err := row.Columns(&sender, &receiver, &amount, &transfer_at); err != nil {
			return err
		}
		fmt.Fprintf(w, "%s %s %f %s\n", sender, receiver, amount, transfer_at.Format(time.RFC3339))
	}
}

void QueryData(google::cloud::spanner::Client client) {
  namespace spanner = ::google::cloud::spanner;

  spanner::SqlStatement select(R"""(
    Graph FinGraph
    MATCH (a:Person)-[o:Owns]->()-[t:Transfers]->()<-[p:Owns]-(b:Person)
    RETURN a.name AS sender,
           b.name AS receiver,
           t.amount,
          t.create_time AS transfer_at
  )""");
  using RowType =
      std::tuple<std::string, std::string, double, spanner::Timestamp>;
  auto rows = client.ExecuteQuery(std::move(select));
  for (auto& row : spanner::StreamOf<RowType>(rows)) {
    if (!row) throw std::move(row).status();
    std::cout << "sender: " << std::get<0>(*row) << "\t";
    std::cout << "receiver: " << std::get<1>(*row) << "\t";
    std::cout << "amount: " << std::get<2>(*row) << "\t";
    std::cout << "transfer_at: " << std::get<3>(*row) << "\n";
  }

  std::cout << "Query completed for [spanner_query_graph_data]\n";
}