Working with NUMERIC data

The Cloud Spanner NUMERIC is an exact numeric data type capable of representing an exact numeric value with a precision of 38 and scale of 9. This page provides an overview of how NUMERIC is represented in client libraries.

Representing NUMERIC in each client library language

To maintain the fidelity of NUMERIC values, each Cloud Spanner client library stores those values in an appropriate data type in the client library language. The following table lists the data types to which NUMERIC is mapped in each supported language.

Language Client library type
C++ spanner::Numeric
C# SpannerNumeric
Go big.Rat
Java BigDecimal
Node.js Big
PHP custom Numeric
Python Decimal
Ruby BigDecimal

Three client libraries, C++, C# and PHP have each implemented a custom type to represent Cloud Spanner SQL's NUMERIC type. All other libraries us an existing type.

The C++ client library spanner::Numeric object does not support arithmetic operations. Instead, convert the contained number to the C++ object of choice. For example, you can extract the number as a string, which would represent the number at full fidelity and with no data loss. If, however, you know in advance that number fits, for example, within the range of std:int64_t or double, then you can access the value as that type.

Adding a NUMERIC column

The following sample shows how to add a NUMERIC column to a table called Venues using the Cloud Spanner client libraries.

C++

void AddNumericColumn(google::cloud::spanner::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);
  auto metadata = client
                      .UpdateDatabase(database, {R"""(
                        ALTER TABLE Venues ADD COLUMN Revenue NUMERIC)"""})
                      .get();
  if (!metadata) throw std::runtime_error(metadata.status().message());
  std::cout << "`Venues` table altered, new DDL:\n"
            << metadata->DebugString() << "\n";
}

C#


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

public class AddNumericColumnAsyncSample
{
    public async Task AddNumericColumnAsync(string projectId, string instanceId, string databaseId)
    {
        string connectionString = $"Data Source=projects/{projectId}/instances/{instanceId}/databases/{databaseId}";
        string alterStatement = "ALTER TABLE Venues ADD COLUMN Revenue NUMERIC";

        using var connection = new SpannerConnection(connectionString);
        using var updateCmd = connection.CreateDdlCommand(alterStatement);
        await updateCmd.ExecuteNonQueryAsync();
        Console.WriteLine("Added the Revenue column.");
    }
}

Go


import (
	"context"
	"fmt"
	"io"

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

func addNumericColumn(w io.Writer, db string) error {
	ctx := context.Background()
	adminClient, err := database.NewDatabaseAdminClient(ctx)
	if err != nil {
		return err
	}
	defer adminClient.Close()

	op, err := adminClient.UpdateDatabaseDdl(ctx, &adminpb.UpdateDatabaseDdlRequest{
		Database: db,
		Statements: []string{
			"ALTER TABLE Venues ADD COLUMN Revenue NUMERIC",
		},
	})
	if err != nil {
		return err
	}
	if err := op.Wait(ctx); err != nil {
		return err
	}
	fmt.Fprintf(w, "Added Revenue column\n")
	return nil
}

Java

import com.google.api.gax.longrunning.OperationFuture;
import com.google.cloud.spanner.DatabaseAdminClient;
import com.google.cloud.spanner.Spanner;
import com.google.cloud.spanner.SpannerOptions;
import com.google.common.collect.ImmutableList;
import com.google.spanner.admin.database.v1.UpdateDatabaseDdlMetadata;
import java.util.concurrent.ExecutionException;

class AddNumericColumnSample {

  static void addNumericColumn() throws InterruptedException, ExecutionException {
    // TODO(developer): Replace these variables before running the sample.
    String projectId = "my-project";
    String instanceId = "my-instance";
    String databaseId = "my-database";

    try (Spanner spanner =
        SpannerOptions.newBuilder().setProjectId(projectId).build().getService()) {
      DatabaseAdminClient adminClient = spanner.getDatabaseAdminClient();
      addNumericColumn(adminClient, instanceId, databaseId);
    }
  }

  static void addNumericColumn(
      DatabaseAdminClient adminClient, String instanceId, String databaseId)
      throws InterruptedException, ExecutionException {
    OperationFuture<Void, UpdateDatabaseDdlMetadata> operation =
        adminClient.updateDatabaseDdl(
            instanceId,
            databaseId,
            ImmutableList.of("ALTER TABLE Venues ADD COLUMN Revenue NUMERIC"),
            null);
    // Wait for the operation to finish.
    // This will throw an ExecutionException if the operation fails.
    operation.get();
    System.out.printf("Successfully added column `Revenue`%n");
  }
}

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

const request = ['ALTER TABLE Venues ADD COLUMN Revenue NUMERIC'];

// Alter existing table to add a column.
const [operation] = await database.updateSchema(request);

console.log(`Waiting for operation on ${databaseId} to complete...`);

await operation.promise();

console.log(
  `Added Revenue column to Venues table in database ${databaseId}.`
);

PHP

use Google\Cloud\Spanner\SpannerClient;

/**
 * Adds a NUMERIC column to a table.
 * Example:
 * ```
 * add_numeric_column($instanceId, $databaseId);
 * ```
 *
 * @param string $instanceId The Spanner instance ID.
 * @param string $databaseId The Spanner database ID.
 */
function add_numeric_column($instanceId, $databaseId)
{
    $spanner = new SpannerClient();
    $instance = $spanner->instance($instanceId);
    $database = $instance->database($databaseId);

    $operation = $database->updateDdl(
        "ALTER TABLE Venues ADD COLUMN Revenue NUMERIC"
    );

    print('Waiting for operation to complete...' . PHP_EOL);
    $operation->pollUntilComplete();

    printf('Added Revenue as a NUMERIC column in Venues table' . PHP_EOL);
}

Python

def add_numeric_column(instance_id, database_id):
    """ Adds a new NUMERIC column to the Venues table in the example database.
    """
    spanner_client = spanner.Client()
    instance = spanner_client.instance(instance_id)

    database = instance.database(database_id)

    operation = database.update_ddl(["ALTER TABLE Venues ADD COLUMN Revenue NUMERIC"])

    print("Waiting for operation to complete...")
    operation.result(120)

    print(
        'Altered table "Venues" on database {} on instance {}.'.format(
            database_id, instance_id
        )
    )

Ruby

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

require "google/cloud/spanner"

spanner  = Google::Cloud::Spanner.new project: project_id
instance = spanner.instance instance_id
database = instance.database database_id

job = database.update statements: [
  "ALTER TABLE Venues ADD COLUMN Revenue NUMERIC"
]

puts "Waiting for database update to complete"

job.wait_until_done!

puts "Added the Revenue as a numeric column in Venues table"

Updating NUMERIC data

The following sample shows how update NUMERIC data using the Cloud Spanner client libraries.

C++

void UpdateDataWithNumeric(google::cloud::spanner::Client client) {
  namespace spanner = ::google::cloud::spanner;
  auto insert_venues =
      spanner::InsertMutationBuilder(
          "Venues", {"VenueId", "VenueName", "Revenue", "LastUpdateTime"})
          .EmplaceRow(1, "Venue 1", spanner::MakeNumeric(35000).value(),
                      spanner::CommitTimestamp())
          .EmplaceRow(6, "Venue 6", spanner::MakeNumeric(104500).value(),
                      spanner::CommitTimestamp())
          .EmplaceRow(
              14, "Venue 14",
              spanner::MakeNumeric("99999999999999999999999999999.99").value(),
              spanner::CommitTimestamp())
          .Build();

  auto commit_result = client.Commit(spanner::Mutations{insert_venues});
  if (!commit_result) {
    throw std::runtime_error(commit_result.status().message());
  }
  std::cout << "Insert was successful [spanner_update_data_with_numeric]\n";
}

C#


using Google.Cloud.Spanner.Data;
using Google.Cloud.Spanner.V1;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

public class UpdateDataWithNumericAsyncSample
{
    public class Venue
    {
        public int VenueId { get; set; }
        public SpannerNumeric Revenue { get; set; }
    }

    public async Task UpdateDataWithNumericAsync(string projectId, string instanceId, string databaseId)
    {
        string connectionString = $"Data Source=projects/{projectId}/instances/{instanceId}/databases/{databaseId}";
        List<Venue> venues = new List<Venue>
        {
            new Venue { VenueId = 4, Revenue = SpannerNumeric.Parse("35000") },
            new Venue { VenueId = 19, Revenue = SpannerNumeric.Parse("104500") },
            new Venue { VenueId = 42, Revenue = SpannerNumeric.Parse("99999999999999999999999999999.99") },
        };
        // Create connection to Cloud Spanner.
        using var connection = new SpannerConnection(connectionString);
        await connection.OpenAsync();

        await Task.WhenAll(venues.Select(venue =>
        {
            // Update rows in the Venues table.
            using var cmd = connection.CreateUpdateCommand("Venues", new SpannerParameterCollection
            {
                    { "VenueId", SpannerDbType.Int64, venue.VenueId },
                    { "Revenue", SpannerDbType.Numeric, venue.Revenue }
            });
            return cmd.ExecuteNonQueryAsync();
        }));

        Console.WriteLine("Data updated.");
    }
}

Go

import (
	"context"
	"io"

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

func updateDataWithNumericColumn(w io.Writer, db string) error {
	ctx := context.Background()

	client, err := spanner.NewClient(ctx, db)
	if err != nil {
		return err
	}
	defer client.Close()

	cols := []string{"VenueId", "Revenue"}
	_, err = client.Apply(ctx, []*spanner.Mutation{
		spanner.Update("Venues", cols, []interface{}{4, "35000"}),
		spanner.Update("Venues", cols, []interface{}{19, "104500"}),
		spanner.Update("Venues", cols, []interface{}{42, "99999999999999999999999999999.99"}),
	})
	return err
}

Java

import com.google.cloud.spanner.DatabaseClient;
import com.google.cloud.spanner.DatabaseId;
import com.google.cloud.spanner.Mutation;
import com.google.cloud.spanner.Spanner;
import com.google.cloud.spanner.SpannerOptions;
import com.google.common.collect.ImmutableList;
import java.math.BigDecimal;

class UpdateNumericDataSample {

  static void updateNumericData() {
    // TODO(developer): Replace these variables before running the sample.
    String projectId = "my-project";
    String instanceId = "my-instance";
    String databaseId = "my-database";

    try (Spanner spanner =
        SpannerOptions.newBuilder().setProjectId(projectId).build().getService()) {
      DatabaseClient client =
          spanner.getDatabaseClient(DatabaseId.of(projectId, instanceId, databaseId));
      updateNumericData(client);
    }
  }

  static void updateNumericData(DatabaseClient client) {
    client.write(
        ImmutableList.of(
            Mutation.newInsertOrUpdateBuilder("Venues")
                .set("VenueId")
                .to(4L)
                .set("Revenue")
                .to(new BigDecimal("35000"))
                .build(),
            Mutation.newInsertOrUpdateBuilder("Venues")
                .set("VenueId")
                .to(19L)
                .set("Revenue")
                .to(new BigDecimal("104500"))
                .build(),
            Mutation.newInsertOrUpdateBuilder("Venues")
                .set("VenueId")
                .to(42L)
                .set("Revenue")
                .to(new BigDecimal("99999999999999999999999999999.99"))
                .build()));
    System.out.println("Venues successfully updated");
  }
}

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);

// Instantiate Spanner table objects.
const venuesTable = database.table('Venues');

const data = [
  {
    VenueId: '4',
    Revenue: Spanner.numeric('35000'),
    LastUpdateTime: 'spanner.commit_timestamp()',
  },
  {
    VenueId: '19',
    Revenue: Spanner.numeric('104500'),
    LastUpdateTime: 'spanner.commit_timestamp()',
  },
  {
    VenueId: '42',
    Revenue: Spanner.numeric('99999999999999999999999999999.99'),
    LastUpdateTime: 'spanner.commit_timestamp()',
  },
];

// Updates rows in the Venues table.
try {
  await venuesTable.update(data);
  console.log('Updated data.');
} catch (err) {
  console.error('ERROR:', err);
} finally {
  // Close the database when finished.
  database.close();
}

PHP

use Google\Cloud\Spanner\SpannerClient;

/**
 * Updates sample data in a table with a NUMERIC column.
 *
 * Before executing this method, a new column Revenue has to be added to the Venues
 * table by applying the DDL statement "ALTER TABLE Venues ADD COLUMN Revenue NUMERIC".
 *
 * Example:
 * ```
 * update_data_with_numeric_column($instanceId, $databaseId);
 * ```
 *
 * @param string $instanceId The Spanner instance ID.
 * @param string $databaseId The Spanner database ID.
 */
function update_data_with_numeric_column($instanceId, $databaseId)
{
    $spanner = new SpannerClient();
    $instance = $spanner->instance($instanceId);
    $database = $instance->database($databaseId);

    $database->transaction(['singleUse' => true])
        ->updateBatch('Venues', [
            ['VenueId' => 4, 'Revenue' => $spanner->numeric("35000")],
            ['VenueId' => 19, 'Revenue' => $spanner->numeric("104500")],
            ['VenueId' => 42, 'Revenue' => $spanner->numeric("99999999999999999999999999999.99")],
        ])
        ->commit();

    print('Updated data.' . PHP_EOL);
}

Python

def update_data_with_numeric(instance_id, database_id):
    """Updates Venues tables in the database with the NUMERIC
    column.

    This updates the `Revenue` column which must be created before
    running this sample. You can add the column by running the
    `add_numeric_column` sample or by running this DDL statement
     against your database:

        ALTER TABLE Venues ADD COLUMN Revenue NUMERIC
    """
    spanner_client = spanner.Client()
    instance = spanner_client.instance(instance_id)

    database = instance.database(database_id)

    with database.batch() as batch:
        batch.update(
            table="Venues",
            columns=("VenueId", "Revenue"),
            values=[
                (4, decimal.Decimal("35000")),
                (19, decimal.Decimal("104500")),
                (42, decimal.Decimal("99999999999999999999999999999.99")),
            ],
        )

    print("Updated data.")

Ruby

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

require "google/cloud/spanner"

spanner = Google::Cloud::Spanner.new project: project_id
client  = spanner.client instance_id, database_id

client.commit do |c|
  c.update "Venues", [
    { VenueId: 4, Revenue: "35000" },
    { VenueId: 19, Revenue: "104500" },
    { VenueId: 42, Revenue: "99999999999999999999999999999.99" }
  ]
end

puts "Updated data"

Query NUMERIC data

The following sample shows how to query NUMERIC data using the Cloud Spanner client libraries.

C++

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

  auto revenue = spanner::MakeNumeric(100000).value();
  spanner::SqlStatement select(
      "SELECT VenueId, Revenue"
      "  FROM Venues"
      " WHERE Revenue < @revenue",
      {{"revenue", spanner::Value(std::move(revenue))}});
  using RowType = std::tuple<std::int64_t, absl::optional<spanner::Numeric>>;

  auto rows = client.ExecuteQuery(select);
  for (auto const& row : spanner::StreamOf<RowType>(rows)) {
    if (!row) throw std::runtime_error(row.status().message());
    std::cout << "VenueId: " << std::get<0>(*row) << "\t";
    auto revenue = std::get<1>(*row).value();
    std::cout << "Revenue: " << revenue.ToString()
              << " (d.16=" << std::setprecision(16)
              << spanner::ToDouble(revenue)
              << ", i*10^2=" << spanner::ToInteger<int>(revenue, 2).value()
              << ")\n";
  }
}

C#


using Google.Cloud.Spanner.Data;
using Google.Cloud.Spanner.V1;
using System.Collections.Generic;
using System.Threading.Tasks;

public class QueryDataWithNumericParameterAsyncSample
{
    public class Venue
    {
        public int VenueId { get; set; }
        public SpannerNumeric Revenue { get; set; }
    }

    public async Task<List<Venue>> QueryDataWithNumericParameterAsync(string projectId, string instanceId, string databaseId)
    {
        string connectionString = $"Data Source=projects/{projectId}/instances/{instanceId}/databases/{databaseId}";

        using var connection = new SpannerConnection(connectionString);
        using var cmd = connection.CreateSelectCommand(
            "SELECT VenueId, Revenue FROM Venues WHERE Revenue < @maxRevenue",
            new SpannerParameterCollection
            {
                { "maxRevenue", SpannerDbType.Numeric, SpannerNumeric.Parse("100000") }
            });

        var venues = new List<Venue>();
        using var reader = await cmd.ExecuteReaderAsync();
        while (await reader.ReadAsync())
        {
            venues.Add(new Venue
            {
                VenueId = reader.GetFieldValue<int>("VenueId"),
                Revenue = reader.GetFieldValue<SpannerNumeric>("Revenue")
            });
        }
        return venues;
    }
}

Go


import (
	"context"
	"fmt"
	"io"
	"math/big"

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

func queryWithNumericParameter(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: `SELECT VenueId, Revenue FROM Venues WHERE Revenue < @revenue`,
		Params: map[string]interface{}{
			"revenue": big.NewRat(100000, 1),
		},
	}
	iter := client.Single().Query(ctx, stmt)
	defer iter.Stop()
	for {
		row, err := iter.Next()
		if err == iterator.Done {
			return nil
		}
		if err != nil {
			return err
		}
		var venueID int64
		var revenue big.Rat
		if err := row.Columns(&venueID, &revenue); err != nil {
			return err
		}
		fmt.Fprintf(w, "%v %v\n", venueID, revenue)
	}
}

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;
import java.math.BigDecimal;

class QueryWithNumericParameterSample {

  static void queryWithNumericParameter() {
    // TODO(developer): Replace these variables before running the sample.
    String projectId = "my-project";
    String instanceId = "my-instance";
    String databaseId = "my-database";

    try (Spanner spanner =
        SpannerOptions.newBuilder().setProjectId(projectId).build().getService()) {
      DatabaseClient client =
          spanner.getDatabaseClient(DatabaseId.of(projectId, instanceId, databaseId));
      queryWithNumericParameter(client);
    }
  }

  static void queryWithNumericParameter(DatabaseClient client) {
    Statement statement =
        Statement.newBuilder(
                "SELECT VenueId, Revenue FROM Venues WHERE Revenue < @numeric")
            .bind("numeric")
            .to(new BigDecimal("100000"))
            .build();
    try (ResultSet resultSet = client.singleUse().executeQuery(statement)) {
      while (resultSet.next()) {
        System.out.printf(
            "%d %s%n", resultSet.getLong("VenueId"), resultSet.getBigDecimal("Revenue"));
      }
    }
  }
}

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);

const fieldType = {
  type: 'numeric',
};

const exampleNumeric = Spanner.numeric('100000');

const query = {
  sql: `SELECT VenueId, VenueName, Revenue FROM Venues
          WHERE Revenue < @revenue`,
  params: {
    revenue: exampleNumeric,
  },
  types: {
    revenue: fieldType,
  },
};

// Queries rows from the Venues table.
try {
  const [rows] = await database.run(query);

  rows.forEach(row => {
    const json = row.toJSON();
    console.log(`VenueId: ${json.VenueId}, Revenue: ${json.Revenue.value}`);
  });
} 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;

/**
 * Queries sample data from the database using SQL with a NUMERIC parameter.
 * Example:
 * ```
 * query_data_with_numeric_parameter($instanceId, $databaseId);
 * ```
 *
 * @param string $instanceId The Spanner instance ID.
 * @param string $databaseId The Spanner database ID.
 */
function query_data_with_numeric_parameter($instanceId, $databaseId)
{
    $spanner = new SpannerClient();
    $instance = $spanner->instance($instanceId);
    $database = $instance->database($databaseId);

    $exampleNumeric = $spanner->numeric("100000");

    $results = $database->execute(
        'SELECT VenueId, Revenue FROM Venues ' .
        'WHERE Revenue < @revenue',
        [
            'parameters' => [
                'revenue' => $exampleNumeric
            ]
        ]
    );

    foreach ($results as $row) {
        printf('VenueId: %s, Revenue: %s' . PHP_EOL,
            $row['VenueId'], $row['Revenue']);
    }
}

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)

example_numeric = decimal.Decimal("100000")
param = {"revenue": example_numeric}
param_type = {"revenue": param_types.NUMERIC}

with database.snapshot() as snapshot:
    results = snapshot.execute_sql(
        "SELECT VenueId, Revenue FROM Venues " "WHERE Revenue < @revenue",
        params=param,
        param_types=param_type,
    )

    for row in results:
        print(u"VenueId: {}, Revenue: {}".format(*row))

Ruby

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

require "google/cloud/spanner"
require "bigdecimal"

spanner = Google::Cloud::Spanner.new project: project_id
client  = spanner.client instance_id, database_id

sql_query = "SELECT VenueId, Revenue FROM Venues WHERE Revenue < @revenue"

params      = { revenue: BigDecimal("100000") }
param_types = { revenue: :NUMERIC }

client.execute(sql_query, params: params, types: param_types).rows.each do |row|
  puts "#{row[:VenueId]} #{row[:Revenue]}"
end

NUMERIC is supported in the JDBC driver using the Java BigDecimal type. For examples of how NUMERIC is used, see the code samples in Using the open-source JDBC driver.

Handling NUMERIC when creating a client library or driver

The NUMERIC type is encoded as a string in decimal or scientific notation within a google.protobuf.Value proto. This proto is wrapped as either a ResultSet, PartialResultSet, or a Mutation depending on whether it is being read or written. ResultSetMetadata will use the NUMERIC TypeCode to indicate that the corresponding value should be read as a NUMERIC.

When working with NUMERIC in a client library or driver you create, observe the following guidance.

  • To read a NUMERIC from the ResultSet:

    1. Read the string_value from the google.protobuf.Value proto when TypeCode is NUMERIC

    2. Convert that string to the relevant type for the given language

  • To write a NUMERIC using Mutations, use the string representation as the string_value in the google.protobuf.Value proto when given the relevant type.