SDK for Go V2 を使用したDynamoDB の例 - AWSSDK コードサンプル
アクションシナリオ

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SDK for Go V2 を使用したDynamoDB の例

次のコード例は、AWS SDK for Go V2 で一般的なシナリオを実装DynamoDB。

「アクション」は、個々のサービス関数の呼び出し方法を示すコードの抜粋です。

「シナリオ」は、同じサービス内で複数の関数を呼び出して、特定のタスクを実行する方法を示すコード例です。

それぞれの例にはGitHub、へのリンクがあり、コンテキストでコードを設定および実行する方法についての説明が記載されています。

アクション

次のコード例は、DynamoDB テーブルを作成する方法を示しています。

SDK for Go V2
注記

他にもありますGitHub。用例一覧を検索し、AWS コード例リポジトリでの設定と実行の方法を確認してください。


// TableBasics encapsulates the Amazon DynamoDB service actions used in the examples.
// It contains a DynamoDB service client that is used to act on the specified table.
type TableBasics struct {
	DynamoDbClient *dynamodb.Client
	TableName      string
}



// CreateMovieTable creates a DynamoDB table with a composite primary key defined as
// a string sort key named `title`, and a numeric partition key named `year`.
// This function uses NewTableExistsWaiter to wait for the table to be created by
// DynamoDB before it returns.
func (basics TableBasics) CreateMovieTable() (*types.TableDescription, error) {
	var tableDesc *types.TableDescription
	table, err := basics.DynamoDbClient.CreateTable(context.TODO(), &dynamodb.CreateTableInput{
		AttributeDefinitions: []types.AttributeDefinition{{
			AttributeName: aws.String("year"),
			AttributeType: types.ScalarAttributeTypeN,
		}, {
			AttributeName: aws.String("title"),
			AttributeType: types.ScalarAttributeTypeS,
		}},
		KeySchema: []types.KeySchemaElement{{
			AttributeName: aws.String("year"),
			KeyType:       types.KeyTypeHash,
		}, {
			AttributeName: aws.String("title"),
			KeyType:       types.KeyTypeRange,
		}},
		TableName: aws.String(basics.TableName),
		ProvisionedThroughput: &types.ProvisionedThroughput{
			ReadCapacityUnits:  aws.Int64(10),
			WriteCapacityUnits: aws.Int64(10),
		},
	})
	if err != nil {
		log.Printf("Couldn't create table %v. Here's why: %v\n", basics.TableName, err)
	} else {
		waiter := dynamodb.NewTableExistsWaiter(basics.DynamoDbClient)
		err = waiter.Wait(context.TODO(), &dynamodb.DescribeTableInput{
			TableName: aws.String(basics.TableName)}, 5*time.Minute)
		if err != nil {
			log.Printf("Wait for table exists failed. Here's why: %v\n", err)
		}
		tableDesc = table.TableDescription
	}
	return tableDesc, err
}

  • API の詳細については、AWS SDK for GoAPI CreateTableリファレンスのを参照してください。

次のコード例は、DynamoDB テーブルを削除する方法を示しています。

SDK for Go V2
注記

他にもありますGitHub。用例一覧を検索し、AWS コード例リポジトリでの設定と実行の方法を確認してください。


// TableBasics encapsulates the Amazon DynamoDB service actions used in the examples.
// It contains a DynamoDB service client that is used to act on the specified table.
type TableBasics struct {
	DynamoDbClient *dynamodb.Client
	TableName      string
}



// DeleteTable deletes the DynamoDB table and all of its data.
func (basics TableBasics) DeleteTable() error {
	_, err := basics.DynamoDbClient.DeleteTable(context.TODO(), &dynamodb.DeleteTableInput{
		TableName: aws.String(basics.TableName)})
	if err != nil {
		log.Printf("Couldn't delete table %v. Here's why: %v\n", basics.TableName, err)
	}
	return err
}

  • API の詳細については、AWS SDK for GoAPI DeleteTableリファレンスのを参照してください。

次のコード例は、DynamoDB テーブルから項目を削除する方法を示しています。

SDK for Go V2
注記

他にもありますGitHub。用例一覧を検索し、AWS コード例リポジトリでの設定と実行の方法を確認してください。


// TableBasics encapsulates the Amazon DynamoDB service actions used in the examples.
// It contains a DynamoDB service client that is used to act on the specified table.
type TableBasics struct {
	DynamoDbClient *dynamodb.Client
	TableName      string
}



// DeleteMovie removes a movie from the DynamoDB table.
func (basics TableBasics) DeleteMovie(movie Movie) error {
	_, err := basics.DynamoDbClient.DeleteItem(context.TODO(), &dynamodb.DeleteItemInput{
		TableName: aws.String(basics.TableName), Key: movie.GetKey(),
	})
	if err != nil {
		log.Printf("Couldn't delete %v from the table. Here's why: %v\n", movie.Title, err)
	}
	return err
}

  • API の詳細については、AWS SDK for GoAPI DeleteItemリファレンスのを参照してください。

次のコード例は、DynamoDB テーブルから項目を取得する方法を示しています。

SDK for Go V2
注記

他にもありますGitHub。用例一覧を検索し、AWS コード例リポジトリでの設定と実行の方法を確認してください。


// TableBasics encapsulates the Amazon DynamoDB service actions used in the examples.
// It contains a DynamoDB service client that is used to act on the specified table.
type TableBasics struct {
	DynamoDbClient *dynamodb.Client
	TableName      string
}



// GetMovie gets movie data from the DynamoDB table by using the primary composite key
// made of title and year.
func (basics TableBasics) GetMovie(title string, year int) (Movie, error) {
	movie := Movie{Title: title, Year: year}
	response, err := basics.DynamoDbClient.GetItem(context.TODO(), &dynamodb.GetItemInput{
		Key: movie.GetKey(), TableName: aws.String(basics.TableName),
	})
	if err != nil {
		log.Printf("Couldn't get info about %v. Here's why: %v\n", title, err)
	} else {
		err = attributevalue.UnmarshalMap(response.Item, &movie)
		if err != nil {
			log.Printf("Couldn't unmarshal response. Here's why: %v\n", err)
		}
	}
	return movie, err
}

  • API の詳細については、AWS SDK for GoAPI GetItemリファレンスのを参照してください。

次のコード例は、DynamoDB テーブルに関する情報を取得する方法を示しています。

SDK for Go V2
注記

他にもありますGitHub。用例一覧を検索し、AWS コード例リポジトリでの設定と実行の方法を確認してください。


// TableBasics encapsulates the Amazon DynamoDB service actions used in the examples.
// It contains a DynamoDB service client that is used to act on the specified table.
type TableBasics struct {
	DynamoDbClient *dynamodb.Client
	TableName      string
}



// TableExists determines whether a DynamoDB table exists.
func (basics TableBasics) TableExists() (bool, error) {
	exists := true
	_, err := basics.DynamoDbClient.DescribeTable(
		context.TODO(), &dynamodb.DescribeTableInput{TableName: aws.String(basics.TableName)},
	)
	if err != nil {
		var notFoundEx *types.ResourceNotFoundException
		if errors.As(err, &notFoundEx) {
			log.Printf("Table %v does not exist.\n", basics.TableName)
			err = nil
		} else {
			log.Printf("Couldn't determine existence of table %v. Here's why: %v\n", basics.TableName, err)
		}
		exists = false
	}
	return exists, err
}

  • API の詳細については、AWS SDK for GoAPI DescribeTableリファレンスのを参照してください。

次のコード例は、DynamoDB テーブルを一覧表示する方法を示しています。

SDK for Go V2
注記

他にもありますGitHub。用例一覧を検索し、AWS コード例リポジトリでの設定と実行の方法を確認してください。


// TableBasics encapsulates the Amazon DynamoDB service actions used in the examples.
// It contains a DynamoDB service client that is used to act on the specified table.
type TableBasics struct {
	DynamoDbClient *dynamodb.Client
	TableName      string
}



// ListTables lists the DynamoDB table names for the current account.
func (basics TableBasics) ListTables() ([]string, error) {
	var tableNames []string
	tables, err := basics.DynamoDbClient.ListTables(
		context.TODO(), &dynamodb.ListTablesInput{})
	if err != nil {
		log.Printf("Couldn't list tables. Here's why: %v\n", err)
	} else {
		tableNames = tables.TableNames
	}
	return tableNames, err
}

  • API の詳細については、AWS SDK for GoAPI ListTablesリファレンスのを参照してください。

次のコード例は、DynamoDB テーブルで項目を配置する方法を示しています。

SDK for Go V2
注記

他にもありますGitHub。用例一覧を検索し、AWS コード例リポジトリでの設定と実行の方法を確認してください。


// TableBasics encapsulates the Amazon DynamoDB service actions used in the examples.
// It contains a DynamoDB service client that is used to act on the specified table.
type TableBasics struct {
	DynamoDbClient *dynamodb.Client
	TableName      string
}



// AddMovie adds a movie the DynamoDB table.
func (basics TableBasics) AddMovie(movie Movie) error {
	item, err := attributevalue.MarshalMap(movie)
	if err != nil {
		panic(err)
	}
	_, err = basics.DynamoDbClient.PutItem(context.TODO(), &dynamodb.PutItemInput{
		TableName: aws.String(basics.TableName), Item: item,
	})
	if err != nil {
		log.Printf("Couldn't add item to table. Here's why: %v\n", err)
	}
	return err
}

  • API の詳細については、AWS SDK for GoAPI PutItemリファレンスのを参照してください。

次のコード例は、DynamoDB テーブルに対してバッチでクエリを実行する方法を示しています。

SDK for Go V2
注記

他にもありますGitHub。用例一覧を検索し、AWS コード例リポジトリでの設定と実行の方法を確認してください。


// TableBasics encapsulates the Amazon DynamoDB service actions used in the examples.
// It contains a DynamoDB service client that is used to act on the specified table.
type TableBasics struct {
	DynamoDbClient *dynamodb.Client
	TableName      string
}



// Query gets all movies in the DynamoDB table that were released in the specified year.
// The function uses the `expression` package to build the key condition expression
// that is used in the query.
func (basics TableBasics) Query(releaseYear int) ([]Movie, error) {
	var err error
	var response *dynamodb.QueryOutput
	var movies []Movie
	keyEx := expression.Key("year").Equal(expression.Value(releaseYear))
	expr, err := expression.NewBuilder().WithKeyCondition(keyEx).Build()
	if err != nil {
		log.Printf("Couldn't build expression for query. Here's why: %v\n", err)
	} else {
		response, err = basics.DynamoDbClient.Query(context.TODO(), &dynamodb.QueryInput{
			TableName:                 aws.String(basics.TableName),
			ExpressionAttributeNames:  expr.Names(),
			ExpressionAttributeValues: expr.Values(),
			KeyConditionExpression:    expr.KeyCondition(),
		})
		if err != nil {
			log.Printf("Couldn't query for movies released in %v. Here's why: %v\n", releaseYear, err)
		} else {
			err = attributevalue.UnmarshalListOfMaps(response.Items, &movies)
			if err != nil {
				log.Printf("Couldn't unmarshal query response. Here's why: %v\n", err)
			}
		}
	}
	return movies, err
}

  • API の詳細については、「AWS SDK for Go API リファレンス」の「Query」を参照してください。

次のコード例は、DynamoDB テーブルで PartiQL ステートメントを実行する方法を示しています。

SDK for Go V2
注記

他にもありますGitHub。用例一覧を検索し、AWS コード例リポジトリでの設定と実行の方法を確認してください。

INSERT ステートメントを使用して項目を追加します。


// AddMovie runs a PartiQL INSERT statement to add a movie to the DynamoDB table.
func (runner PartiQLRunner) AddMovie(movie Movie) error {
	params, err := attributevalue.MarshalList([]interface{}{movie.Title, movie.Year, movie.Info})
	if err != nil {
		panic(err)
	}
	_, err = runner.DynamoDbClient.ExecuteStatement(context.TODO(), &dynamodb.ExecuteStatementInput{
		Statement: aws.String(
			fmt.Sprintf("INSERT INTO \"%v\" VALUE {'title': ?, 'year': ?, 'info': ?}",
				runner.TableName)),
		Parameters: params,
	})
	if err != nil {
		log.Printf("Couldn't insert an item with PartiQL. Here's why: %v\n", err)
	}
	return err
}

SELECT ステートメントを使用して項目を取得します。


// GetMovie runs a PartiQL SELECT statement to get a movie from the DynamoDB table by
// title and year.
func (runner PartiQLRunner) GetMovie(title string, year int) (Movie, error) {
	var movie Movie
	params, err := attributevalue.MarshalList([]interface{}{title, year})
	if err != nil {
		panic(err)
	}
	response, err := runner.DynamoDbClient.ExecuteStatement(context.TODO(), &dynamodb.ExecuteStatementInput{
		Statement: aws.String(
			fmt.Sprintf("SELECT * FROM \"%v\" WHERE title=? AND year=?",
				runner.TableName)),
		Parameters: params,
	})
	if err != nil {
		log.Printf("Couldn't get info about %v. Here's why: %v\n", title, err)
	} else {
		err = attributevalue.UnmarshalMap(response.Items[0], &movie)
		if err != nil {
			log.Printf("Couldn't unmarshal response. Here's why: %v\n", err)
		}
	}
	return movie, err
}

SELECT ステートメントを使用して、項目のリストを取得し、結果を射影します。


// GetAllMovies runs a PartiQL SELECT statement to get all movies from the DynamoDB table.
// The results are projected to return only the title and rating of each movie.
func (runner PartiQLRunner) GetAllMovies() ([]map[string]interface{}, error) {
	var output []map[string]interface{}
	response, err := runner.DynamoDbClient.ExecuteStatement(context.TODO(), &dynamodb.ExecuteStatementInput{
		Statement: aws.String(
			fmt.Sprintf("SELECT title, info.rating FROM \"%v\"", runner.TableName)),
	})
	if err != nil {
		log.Printf("Couldn't get movies. Here's why: %v\n", err)
	} else {
		err = attributevalue.UnmarshalListOfMaps(response.Items, &output)
		if err != nil {
			log.Printf("Couldn't unmarshal response. Here's why: %v\n", err)
		}
	}
	return output, err
}

UPDATE ステートメントを使用してアイテムを更新します。


// UpdateMovie runs a PartiQL UPDATE statement to update the rating of a movie that
// already exists in the DynamoDB table.
func (runner PartiQLRunner) UpdateMovie(movie Movie, rating float64) error {
	params, err := attributevalue.MarshalList([]interface{}{rating, movie.Title, movie.Year})
	if err != nil {
		panic(err)
	}
	_, err = runner.DynamoDbClient.ExecuteStatement(context.TODO(), &dynamodb.ExecuteStatementInput{
		Statement: aws.String(
			fmt.Sprintf("UPDATE \"%v\" SET info.rating=? WHERE title=? AND year=?",
				runner.TableName)),
		Parameters: params,
	})
	if err != nil {
		log.Printf("Couldn't update movie %v. Here's why: %v\n", movie.Title, err)
	}
	return err
}

DELETE ステートメントを使用して項目を削除します。


// DeleteMovie runs a PartiQL DELETE statement to remove a movie from the DynamoDB table.
func (runner PartiQLRunner) DeleteMovie(movie Movie) error {
	params, err := attributevalue.MarshalList([]interface{}{movie.Title, movie.Year})
	if err != nil {
		panic(err)
	}
	_, err = runner.DynamoDbClient.ExecuteStatement(context.TODO(), &dynamodb.ExecuteStatementInput{
		Statement: aws.String(
			fmt.Sprintf("DELETE FROM \"%v\" WHERE title=? AND year=?",
				runner.TableName)),
		Parameters: params,
	})
	if err != nil {
		log.Printf("Couldn't delete %v from the table. Here's why: %v\n", movie.Title, err)
	}
	return err
}

  • API の詳細については、AWS SDK for GoAPI ExecuteStatementリファレンスのを参照してください。

次のコード例は、DynamoDB テーブルで PartiQL ステートメントのバッチを実行する方法を示しています。

SDK for Go V2
注記

他にもありますGitHub。用例一覧を検索し、AWS コード例リポジトリでの設定と実行の方法を確認してください。

INSERT ステートメントのバッチを使用して項目を追加します。


// AddMovieBatch runs a batch of PartiQL INSERT statements to add multiple movies to the
// DynamoDB table.
func (runner PartiQLRunner) AddMovieBatch(movies []Movie) error {
	statementRequests := make([]types.BatchStatementRequest, len(movies))
	for index, movie := range movies {
		params, err := attributevalue.MarshalList([]interface{}{movie.Title, movie.Year, movie.Info})
		if err != nil {
			panic(err)
		}
		statementRequests[index] = types.BatchStatementRequest{
			Statement: aws.String(fmt.Sprintf(
				"INSERT INTO \"%v\" VALUE {'title': ?, 'year': ?, 'info': ?}", runner.TableName)),
			Parameters: params,
		}
	}

	_, err := runner.DynamoDbClient.BatchExecuteStatement(context.TODO(), &dynamodb.BatchExecuteStatementInput{
		Statements: statementRequests,
	})
	if err != nil {
		log.Printf("Couldn't insert a batch of items with PartiQL. Here's why: %v\n", err)
	}
	return err
}

SELECT ステートメントのバッチを使用して項目を取得します。


// GetMovieBatch runs a batch of PartiQL SELECT statements to get multiple movies from
// the DynamoDB table by title and year.
func (runner PartiQLRunner) GetMovieBatch(movies []Movie) ([]Movie, error) {
	statementRequests := make([]types.BatchStatementRequest, len(movies))
	for index, movie := range movies {
		params, err := attributevalue.MarshalList([]interface{}{movie.Title, movie.Year})
		if err != nil {
			panic(err)
		}
		statementRequests[index] = types.BatchStatementRequest{
			Statement: aws.String(
				fmt.Sprintf("SELECT * FROM \"%v\" WHERE title=? AND year=?", runner.TableName)),
			Parameters: params,
		}
	}

	output, err := runner.DynamoDbClient.BatchExecuteStatement(context.TODO(), &dynamodb.BatchExecuteStatementInput{
		Statements: statementRequests,
	})
	var outMovies []Movie
	if err != nil {
		log.Printf("Couldn't get a batch of items with PartiQL. Here's why: %v\n", err)
	} else {
		for _, response := range output.Responses {
			var movie Movie
			err = attributevalue.UnmarshalMap(response.Item, &movie)
			if err != nil {
				log.Printf("Couldn't unmarshal response. Here's why: %v\n", err)
			} else {
				outMovies = append(outMovies, movie)
			}
		}
	}
	return outMovies, err
}

UPDATE ステートメントのバッチを使用して項目を更新します。


// UpdateMovieBatch runs a batch of PartiQL UPDATE statements to update the rating of
// multiple movies that already exist in the DynamoDB table.
func (runner PartiQLRunner) UpdateMovieBatch(movies []Movie, ratings []float64) error {
	statementRequests := make([]types.BatchStatementRequest, len(movies))
	for index, movie := range movies {
		params, err := attributevalue.MarshalList([]interface{}{ratings[index], movie.Title, movie.Year})
		if err != nil {
			panic(err)
		}
		statementRequests[index] = types.BatchStatementRequest{
			Statement: aws.String(
				fmt.Sprintf("UPDATE \"%v\" SET info.rating=? WHERE title=? AND year=?", runner.TableName)),
			Parameters: params,
		}
	}

	_, err := runner.DynamoDbClient.BatchExecuteStatement(context.TODO(), &dynamodb.BatchExecuteStatementInput{
		Statements: statementRequests,
	})
	if err != nil {
		log.Printf("Couldn't update the batch of movies. Here's why: %v\n", err)
	}
	return err
}

DELETE ステートメントのバッチを使用して項目を削除します。


// DeleteMovieBatch runs a batch of PartiQL DELETE statements to remove multiple movies
// from the DynamoDB table.
func (runner PartiQLRunner) DeleteMovieBatch(movies []Movie) error {
	statementRequests := make([]types.BatchStatementRequest, len(movies))
	for index, movie := range movies {
		params, err := attributevalue.MarshalList([]interface{}{movie.Title, movie.Year})
		if err != nil {
			panic(err)
		}
		statementRequests[index] = types.BatchStatementRequest{
			Statement: aws.String(
				fmt.Sprintf("DELETE FROM \"%v\" WHERE title=? AND year=?", runner.TableName)),
			Parameters: params,
		}
	}

	_, err := runner.DynamoDbClient.BatchExecuteStatement(context.TODO(), &dynamodb.BatchExecuteStatementInput{
		Statements: statementRequests,
	})
	if err != nil {
		log.Printf("Couldn't delete the batch of movies. Here's why: %v\n", err)
	}
	return err
}

  • API の詳細については、AWS SDK for GoAPI BatchExecuteStatementリファレンスのを参照してください。

次のコード例は、DynamoDB テーブルをスキャンする方法を示しています。

SDK for Go V2
注記

他にもありますGitHub。用例一覧を検索し、AWS コード例リポジトリでの設定と実行の方法を確認してください。


// TableBasics encapsulates the Amazon DynamoDB service actions used in the examples.
// It contains a DynamoDB service client that is used to act on the specified table.
type TableBasics struct {
	DynamoDbClient *dynamodb.Client
	TableName      string
}



// Scan gets all movies in the DynamoDB table that were released in a range of years
// and projects them to return a reduced set of fields.
// The function uses the `expression` package to build the filter and projection
// expressions.
func (basics TableBasics) Scan(startYear int, endYear int) ([]Movie, error) {
	var movies []Movie
	var err error
	var response *dynamodb.ScanOutput
	filtEx := expression.Name("year").Between(expression.Value(startYear), expression.Value(endYear))
	projEx := expression.NamesList(
		expression.Name("year"), expression.Name("title"), expression.Name("info.rating"))
	expr, err := expression.NewBuilder().WithFilter(filtEx).WithProjection(projEx).Build()
	if err != nil {
		log.Printf("Couldn't build expressions for scan. Here's why: %v\n", err)
	} else {
		response, err = basics.DynamoDbClient.Scan(context.TODO(), &dynamodb.ScanInput{
			TableName:                 aws.String(basics.TableName),
			ExpressionAttributeNames:  expr.Names(),
			ExpressionAttributeValues: expr.Values(),
			FilterExpression:          expr.Filter(),
			ProjectionExpression:      expr.Projection(),
		})
		if err != nil {
			log.Printf("Couldn't scan for movies released between %v and %v. Here's why: %v\n",
				startYear, endYear, err)
		} else {
			err = attributevalue.UnmarshalListOfMaps(response.Items, &movies)
			if err != nil {
				log.Printf("Couldn't unmarshal query response. Here's why: %v\n", err)
			}
		}
	}
	return movies, err
}

  • API の詳細については、「AWS SDK for Go API リファレンス」の「Scan」を参照してください。

次のコード例は、DynamoDB テーブルで項目を更新する方法を示しています。

SDK for Go V2
注記

他にもありますGitHub。用例一覧を検索し、AWS コード例リポジトリでの設定と実行の方法を確認してください。


// TableBasics encapsulates the Amazon DynamoDB service actions used in the examples.
// It contains a DynamoDB service client that is used to act on the specified table.
type TableBasics struct {
	DynamoDbClient *dynamodb.Client
	TableName      string
}



// UpdateMovie updates the rating and plot of a movie that already exists in the
// DynamoDB table. This function uses the `expression` package to build the update
// expression.
func (basics TableBasics) UpdateMovie(movie Movie) (map[string]map[string]interface{}, error) {
	var err error
	var response *dynamodb.UpdateItemOutput
	var attributeMap map[string]map[string]interface{}
	update := expression.Set(expression.Name("info.rating"), expression.Value(movie.Info["rating"]))
	update.Set(expression.Name("info.plot"), expression.Value(movie.Info["plot"]))
	expr, err := expression.NewBuilder().WithUpdate(update).Build()
	if err != nil {
		log.Printf("Couldn't build expression for update. Here's why: %v\n", err)
	} else {
		response, err = basics.DynamoDbClient.UpdateItem(context.TODO(), &dynamodb.UpdateItemInput{
			TableName:                 aws.String(basics.TableName),
			Key:                       movie.GetKey(),
			ExpressionAttributeNames:  expr.Names(),
			ExpressionAttributeValues: expr.Values(),
			UpdateExpression:          expr.Update(),
			ReturnValues:              types.ReturnValueUpdatedNew,
		})
		if err != nil {
			log.Printf("Couldn't update movie %v. Here's why: %v\n", movie.Title, err)
		} else {
			err = attributevalue.UnmarshalMap(response.Attributes, &attributeMap)
			if err != nil {
				log.Printf("Couldn't unmarshall update response. Here's why: %v\n", err)
			}
		}
	}
	return attributeMap, err
}

  • API の詳細については、AWS SDK for GoAPI UpdateItemリファレンスのを参照してください。

次のコード例は、DynamoDB 項目のバッチを書き込む方法を示しています。

SDK for Go V2
注記

他にもありますGitHub。用例一覧を検索し、AWS コード例リポジトリでの設定と実行の方法を確認してください。


// TableBasics encapsulates the Amazon DynamoDB service actions used in the examples.
// It contains a DynamoDB service client that is used to act on the specified table.
type TableBasics struct {
	DynamoDbClient *dynamodb.Client
	TableName      string
}



// AddMovieBatch adds a slice of movies to the DynamoDB table. The function sends
// batches of 25 movies to DynamoDB until all movies are added or it reaches the
// specified maximum.
func (basics TableBasics) AddMovieBatch(movies []Movie, maxMovies int) (int, error) {
	var err error
	var item map[string]types.AttributeValue
	written := 0
	batchSize := 25 // DynamoDB allows a maximum batch size of 25 items.
	start := 0
	end := start + batchSize
	for start < maxMovies && start < len(movies) {
		var writeReqs []types.WriteRequest
		if end > len(movies) {
			end = len(movies)
		}
		for _, movie := range movies[start:end] {
			item, err = attributevalue.MarshalMap(movie)
			if err != nil {
				log.Printf("Couldn't marshal movie %v for batch writing. Here's why: %v\n", movie.Title, err)
			} else {
				writeReqs = append(
					writeReqs,
					types.WriteRequest{PutRequest: &types.PutRequest{Item: item}},
				)
			}
		}
		_, err = basics.DynamoDbClient.BatchWriteItem(context.TODO(), &dynamodb.BatchWriteItemInput{
			RequestItems: map[string][]types.WriteRequest{basics.TableName: writeReqs}})
		if err != nil {
			log.Printf("Couldn't add a batch of movies to %v. Here's why: %v\n", basics.TableName, err)
		} else {
			written += len(writeReqs)
		}
		start = end
		end += batchSize
	}

	return written, err
}

  • API の詳細については、AWS SDK for GoAPI BatchWriteItemリファレンスのを参照してください。

シナリオ

次のコード例は、以下の操作方法を示しています。

  • 映画データを保持できるテーブルを作成する。

  • テーブルに 1 つの映画を入れ、取得して更新する。

  • サンプル JSON ファイルから映画データをテーブルに書き込む。

  • 特定の年にリリースされた映画を照会する。

  • 何年もの間にリリースされた映画をスキャンする。

  • テーブルからムービーを削除し、テーブルを削除します。

SDK for Go V2
注記

他にもありますGitHub。用例一覧を検索し、AWS コード例リポジトリでの設定と実行の方法を確認してください。

DynamoDB アクションを呼び出す構造体およびメソッドを作成します。


// TableBasics encapsulates the Amazon DynamoDB service actions used in the examples.
// It contains a DynamoDB service client that is used to act on the specified table.
type TableBasics struct {
	DynamoDbClient *dynamodb.Client
	TableName      string
}



// TableExists determines whether a DynamoDB table exists.
func (basics TableBasics) TableExists() (bool, error) {
	exists := true
	_, err := basics.DynamoDbClient.DescribeTable(
		context.TODO(), &dynamodb.DescribeTableInput{TableName: aws.String(basics.TableName)},
	)
	if err != nil {
		var notFoundEx *types.ResourceNotFoundException
		if errors.As(err, &notFoundEx) {
			log.Printf("Table %v does not exist.\n", basics.TableName)
			err = nil
		} else {
			log.Printf("Couldn't determine existence of table %v. Here's why: %v\n", basics.TableName, err)
		}
		exists = false
	}
	return exists, err
}



// CreateMovieTable creates a DynamoDB table with a composite primary key defined as
// a string sort key named `title`, and a numeric partition key named `year`.
// This function uses NewTableExistsWaiter to wait for the table to be created by
// DynamoDB before it returns.
func (basics TableBasics) CreateMovieTable() (*types.TableDescription, error) {
	var tableDesc *types.TableDescription
	table, err := basics.DynamoDbClient.CreateTable(context.TODO(), &dynamodb.CreateTableInput{
		AttributeDefinitions: []types.AttributeDefinition{{
			AttributeName: aws.String("year"),
			AttributeType: types.ScalarAttributeTypeN,
		}, {
			AttributeName: aws.String("title"),
			AttributeType: types.ScalarAttributeTypeS,
		}},
		KeySchema: []types.KeySchemaElement{{
			AttributeName: aws.String("year"),
			KeyType:       types.KeyTypeHash,
		}, {
			AttributeName: aws.String("title"),
			KeyType:       types.KeyTypeRange,
		}},
		TableName: aws.String(basics.TableName),
		ProvisionedThroughput: &types.ProvisionedThroughput{
			ReadCapacityUnits:  aws.Int64(10),
			WriteCapacityUnits: aws.Int64(10),
		},
	})
	if err != nil {
		log.Printf("Couldn't create table %v. Here's why: %v\n", basics.TableName, err)
	} else {
		waiter := dynamodb.NewTableExistsWaiter(basics.DynamoDbClient)
		err = waiter.Wait(context.TODO(), &dynamodb.DescribeTableInput{
			TableName: aws.String(basics.TableName)}, 5*time.Minute)
		if err != nil {
			log.Printf("Wait for table exists failed. Here's why: %v\n", err)
		}
		tableDesc = table.TableDescription
	}
	return tableDesc, err
}



// ListTables lists the DynamoDB table names for the current account.
func (basics TableBasics) ListTables() ([]string, error) {
	var tableNames []string
	tables, err := basics.DynamoDbClient.ListTables(
		context.TODO(), &dynamodb.ListTablesInput{})
	if err != nil {
		log.Printf("Couldn't list tables. Here's why: %v\n", err)
	} else {
		tableNames = tables.TableNames
	}
	return tableNames, err
}



// AddMovie adds a movie the DynamoDB table.
func (basics TableBasics) AddMovie(movie Movie) error {
	item, err := attributevalue.MarshalMap(movie)
	if err != nil {
		panic(err)
	}
	_, err = basics.DynamoDbClient.PutItem(context.TODO(), &dynamodb.PutItemInput{
		TableName: aws.String(basics.TableName), Item: item,
	})
	if err != nil {
		log.Printf("Couldn't add item to table. Here's why: %v\n", err)
	}
	return err
}



// UpdateMovie updates the rating and plot of a movie that already exists in the
// DynamoDB table. This function uses the `expression` package to build the update
// expression.
func (basics TableBasics) UpdateMovie(movie Movie) (map[string]map[string]interface{}, error) {
	var err error
	var response *dynamodb.UpdateItemOutput
	var attributeMap map[string]map[string]interface{}
	update := expression.Set(expression.Name("info.rating"), expression.Value(movie.Info["rating"]))
	update.Set(expression.Name("info.plot"), expression.Value(movie.Info["plot"]))
	expr, err := expression.NewBuilder().WithUpdate(update).Build()
	if err != nil {
		log.Printf("Couldn't build expression for update. Here's why: %v\n", err)
	} else {
		response, err = basics.DynamoDbClient.UpdateItem(context.TODO(), &dynamodb.UpdateItemInput{
			TableName:                 aws.String(basics.TableName),
			Key:                       movie.GetKey(),
			ExpressionAttributeNames:  expr.Names(),
			ExpressionAttributeValues: expr.Values(),
			UpdateExpression:          expr.Update(),
			ReturnValues:              types.ReturnValueUpdatedNew,
		})
		if err != nil {
			log.Printf("Couldn't update movie %v. Here's why: %v\n", movie.Title, err)
		} else {
			err = attributevalue.UnmarshalMap(response.Attributes, &attributeMap)
			if err != nil {
				log.Printf("Couldn't unmarshall update response. Here's why: %v\n", err)
			}
		}
	}
	return attributeMap, err
}



// AddMovieBatch adds a slice of movies to the DynamoDB table. The function sends
// batches of 25 movies to DynamoDB until all movies are added or it reaches the
// specified maximum.
func (basics TableBasics) AddMovieBatch(movies []Movie, maxMovies int) (int, error) {
	var err error
	var item map[string]types.AttributeValue
	written := 0
	batchSize := 25 // DynamoDB allows a maximum batch size of 25 items.
	start := 0
	end := start + batchSize
	for start < maxMovies && start < len(movies) {
		var writeReqs []types.WriteRequest
		if end > len(movies) {
			end = len(movies)
		}
		for _, movie := range movies[start:end] {
			item, err = attributevalue.MarshalMap(movie)
			if err != nil {
				log.Printf("Couldn't marshal movie %v for batch writing. Here's why: %v\n", movie.Title, err)
			} else {
				writeReqs = append(
					writeReqs,
					types.WriteRequest{PutRequest: &types.PutRequest{Item: item}},
				)
			}
		}
		_, err = basics.DynamoDbClient.BatchWriteItem(context.TODO(), &dynamodb.BatchWriteItemInput{
			RequestItems: map[string][]types.WriteRequest{basics.TableName: writeReqs}})
		if err != nil {
			log.Printf("Couldn't add a batch of movies to %v. Here's why: %v\n", basics.TableName, err)
		} else {
			written += len(writeReqs)
		}
		start = end
		end += batchSize
	}

	return written, err
}



// GetMovie gets movie data from the DynamoDB table by using the primary composite key
// made of title and year.
func (basics TableBasics) GetMovie(title string, year int) (Movie, error) {
	movie := Movie{Title: title, Year: year}
	response, err := basics.DynamoDbClient.GetItem(context.TODO(), &dynamodb.GetItemInput{
		Key: movie.GetKey(), TableName: aws.String(basics.TableName),
	})
	if err != nil {
		log.Printf("Couldn't get info about %v. Here's why: %v\n", title, err)
	} else {
		err = attributevalue.UnmarshalMap(response.Item, &movie)
		if err != nil {
			log.Printf("Couldn't unmarshal response. Here's why: %v\n", err)
		}
	}
	return movie, err
}



// Query gets all movies in the DynamoDB table that were released in the specified year.
// The function uses the `expression` package to build the key condition expression
// that is used in the query.
func (basics TableBasics) Query(releaseYear int) ([]Movie, error) {
	var err error
	var response *dynamodb.QueryOutput
	var movies []Movie
	keyEx := expression.Key("year").Equal(expression.Value(releaseYear))
	expr, err := expression.NewBuilder().WithKeyCondition(keyEx).Build()
	if err != nil {
		log.Printf("Couldn't build expression for query. Here's why: %v\n", err)
	} else {
		response, err = basics.DynamoDbClient.Query(context.TODO(), &dynamodb.QueryInput{
			TableName:                 aws.String(basics.TableName),
			ExpressionAttributeNames:  expr.Names(),
			ExpressionAttributeValues: expr.Values(),
			KeyConditionExpression:    expr.KeyCondition(),
		})
		if err != nil {
			log.Printf("Couldn't query for movies released in %v. Here's why: %v\n", releaseYear, err)
		} else {
			err = attributevalue.UnmarshalListOfMaps(response.Items, &movies)
			if err != nil {
				log.Printf("Couldn't unmarshal query response. Here's why: %v\n", err)
			}
		}
	}
	return movies, err
}



// Scan gets all movies in the DynamoDB table that were released in a range of years
// and projects them to return a reduced set of fields.
// The function uses the `expression` package to build the filter and projection
// expressions.
func (basics TableBasics) Scan(startYear int, endYear int) ([]Movie, error) {
	var movies []Movie
	var err error
	var response *dynamodb.ScanOutput
	filtEx := expression.Name("year").Between(expression.Value(startYear), expression.Value(endYear))
	projEx := expression.NamesList(
		expression.Name("year"), expression.Name("title"), expression.Name("info.rating"))
	expr, err := expression.NewBuilder().WithFilter(filtEx).WithProjection(projEx).Build()
	if err != nil {
		log.Printf("Couldn't build expressions for scan. Here's why: %v\n", err)
	} else {
		response, err = basics.DynamoDbClient.Scan(context.TODO(), &dynamodb.ScanInput{
			TableName:                 aws.String(basics.TableName),
			ExpressionAttributeNames:  expr.Names(),
			ExpressionAttributeValues: expr.Values(),
			FilterExpression:          expr.Filter(),
			ProjectionExpression:      expr.Projection(),
		})
		if err != nil {
			log.Printf("Couldn't scan for movies released between %v and %v. Here's why: %v\n",
				startYear, endYear, err)
		} else {
			err = attributevalue.UnmarshalListOfMaps(response.Items, &movies)
			if err != nil {
				log.Printf("Couldn't unmarshal query response. Here's why: %v\n", err)
			}
		}
	}
	return movies, err
}



// DeleteMovie removes a movie from the DynamoDB table.
func (basics TableBasics) DeleteMovie(movie Movie) error {
	_, err := basics.DynamoDbClient.DeleteItem(context.TODO(), &dynamodb.DeleteItemInput{
		TableName: aws.String(basics.TableName), Key: movie.GetKey(),
	})
	if err != nil {
		log.Printf("Couldn't delete %v from the table. Here's why: %v\n", movie.Title, err)
	}
	return err
}



// DeleteTable deletes the DynamoDB table and all of its data.
func (basics TableBasics) DeleteTable() error {
	_, err := basics.DynamoDbClient.DeleteTable(context.TODO(), &dynamodb.DeleteTableInput{
		TableName: aws.String(basics.TableName)})
	if err != nil {
		log.Printf("Couldn't delete table %v. Here's why: %v\n", basics.TableName, err)
	}
	return err
}

対話型シナリオを実行してテーブルを作成し、そのテーブルに対してアクションを実行します。


// RunMovieScenario is an interactive example that shows you how to use the AWS SDK for Go
// to create and use an Amazon DynamoDB table that stores data about movies.
//
//   1. Create a table that can hold movie data.
//   2. Put, get, and update a single movie in the table.
//   3. Write movie data to the table from a sample JSON file.
//   4. Query for movies that were released in a given year.
//   5. Scan for movies that were released in a range of years.
//   6. Delete a movie from the table.
//   7. Delete the table.
//
// This example creates a DynamoDB service client from the specified sdkConfig so that
// you can replace it with a mocked or stubbed config for unit testing.
//
// It uses a questioner from the `demotools` package to get input during the example.
// This package can be found in the ..\..\demotools folder of this repo.
//
// The specified movie sampler is used to get sample data from a URL that is loaded
// into the named table.
func RunMovieScenario(
	sdkConfig aws.Config, questioner demotools.IQuestioner, tableName string,
	movieSampler actions.IMovieSampler) {
	defer func() {
		if r := recover(); r != nil {
			fmt.Printf("Something went wrong with the demo.")
		}
	}()

	log.Println(strings.Repeat("-", 88))
	log.Println("Welcome to the Amazon DynamoDB getting started demo.")
	log.Println(strings.Repeat("-", 88))

	tableBasics := actions.TableBasics{TableName: tableName,
		DynamoDbClient: dynamodb.NewFromConfig(sdkConfig)}

	exists, err := tableBasics.TableExists()
	if err != nil {
		panic(err)
	}
	if !exists {
		log.Printf("Creating table %v...\n", tableName)
		_, err = tableBasics.CreateMovieTable()
		if err != nil {
			panic(err)
		} else {
			log.Printf("Created table %v.\n", tableName)
		}
	} else {
		log.Printf("Table %v already exists.\n", tableName)
	}

	var customMovie actions.Movie
	customMovie.Title = questioner.Ask("Enter a movie title to add to the table:",
		[]demotools.IAnswerValidator{demotools.NotEmpty{}})
	customMovie.Year = questioner.AskInt("What year was it released?",
		[]demotools.IAnswerValidator{demotools.NotEmpty{}, demotools.InIntRange{
			Lower: 1900, Upper: 2030}})
	customMovie.Info = map[string]interface{}{}
	customMovie.Info["rating"] = questioner.AskFloat64(
		"Enter a rating between 1 and 10:", []demotools.IAnswerValidator{
			demotools.NotEmpty{}, demotools.InFloatRange{Lower: 1, Upper: 10}})
	customMovie.Info["plot"] = questioner.Ask("What's the plot? ",
		[]demotools.IAnswerValidator{demotools.NotEmpty{}})
	err = tableBasics.AddMovie(customMovie)
	if err == nil {
		log.Printf("Added %v to the movie table.\n", customMovie.Title)
	}
	log.Println(strings.Repeat("-", 88))

	log.Printf("Let's update your movie. You previously rated it %v.\n", customMovie.Info["rating"])
	customMovie.Info["rating"] = questioner.AskFloat64(
		"What new rating would you give it?", []demotools.IAnswerValidator{
			demotools.NotEmpty{}, demotools.InFloatRange{Lower: 1, Upper: 10}})
	log.Printf("You summarized the plot as '%v'.\n", customMovie.Info["plot"])
	customMovie.Info["plot"] = questioner.Ask("What would you say now?",
		[]demotools.IAnswerValidator{demotools.NotEmpty{}})
	attributes, err := tableBasics.UpdateMovie(customMovie)
	if err == nil {
		log.Printf("Updated %v with new values.\n", customMovie.Title)
		for _, attVal := range attributes {
			for valKey, val := range attVal {
				log.Printf("\t%v: %v\n", valKey, val)
			}
		}
	}
	log.Println(strings.Repeat("-", 88))

	log.Printf("Getting movie data from %v and adding 250 movies to the table...\n",
		movieSampler.GetURL())
	movies := movieSampler.GetSampleMovies()
	written, err := tableBasics.AddMovieBatch(movies, 250)
	if err != nil {
		panic(err)
	} else {
		log.Printf("Added %v movies to the table.\n", written)
	}

	show := 10
	if show > written {
		show = written
	}
	log.Printf("The first %v movies in the table are:", show)
	for index, movie := range movies[:show] {
		log.Printf("\t%v. %v\n", index+1, movie.Title)
	}
	movieIndex := questioner.AskInt(
		"Enter the number of a movie to get info about it: ", []demotools.IAnswerValidator{
			demotools.InIntRange{Lower: 1, Upper: show}},
	)
	movie, err := tableBasics.GetMovie(movies[movieIndex-1].Title, movies[movieIndex-1].Year)
	if err == nil {
		log.Println(movie)
	}
	log.Println(strings.Repeat("-", 88))

	log.Println("Let's get a list of movies released in a given year.")
	releaseYear := questioner.AskInt("Enter a year between 1972 and 2018: ",
		[]demotools.IAnswerValidator{demotools.InIntRange{Lower: 1972, Upper: 2018}},
	)
	releases, err := tableBasics.Query(releaseYear)
	if err == nil {
		if len(releases) == 0 {
			log.Printf("I couldn't find any movies released in %v!\n", releaseYear)
		} else {
			for _, movie = range releases {
				log.Println(movie)
			}
		}
	}
	log.Println(strings.Repeat("-", 88))

	log.Println("Now let's scan for movies released in a range of years.")
	startYear := questioner.AskInt("Enter a year: ", []demotools.IAnswerValidator{
		demotools.InIntRange{Lower: 1972, Upper: 2018}})
	endYear := questioner.AskInt("Enter another year: ", []demotools.IAnswerValidator{
		demotools.InIntRange{Lower: 1972, Upper: 2018}})
	releases, err = tableBasics.Scan(startYear, endYear)
	if err == nil {
		if len(releases) == 0 {
			log.Printf("I couldn't find any movies released between %v and %v!\n", startYear, endYear)
		} else {
			log.Printf("Found %v movies. In this list, the plot is <nil> because "+
				"we used a projection expression when scanning for items to return only "+
				"the title, year, and rating.\n", len(releases))
			for _, movie = range releases {
				log.Println(movie)
			}
		}
	}
	log.Println(strings.Repeat("-", 88))

	var tables []string
	if questioner.AskBool("Do you want to list all of your tables? (y/n) ", "y") {
		tables, err = tableBasics.ListTables()
		if err == nil {
			log.Printf("Found %v tables:", len(tables))
			for _, table := range tables {
				log.Printf("\t%v", table)
			}
		}
	}
	log.Println(strings.Repeat("-", 88))

	log.Printf("Let's remove your movie '%v'.\n", customMovie.Title)
	if questioner.AskBool("Do you want to delete it from the table? (y/n) ", "y") {
		err = tableBasics.DeleteMovie(customMovie)
	}
	if err == nil {
		log.Printf("Deleted %v.\n", customMovie.Title)
	}

	if questioner.AskBool("Delete the table, too? (y/n)", "y") {
		err = tableBasics.DeleteTable()
	} else {
		log.Println("Don't forget to delete the table when you're done or you might " +
			"incur charges on your account.")
	}
	if err == nil {
		log.Printf("Deleted table %v.\n", tableBasics.TableName)
	}

	log.Println(strings.Repeat("-", 88))
	log.Println("Thanks for watching!")
	log.Println(strings.Repeat("-", 88))
}

次のコード例は、以下の操作方法を示しています。

  • 複数の SELECT ステートメントを実行して、項目のバッチを取得する。

  • 複数の INSERT ステートメントを実行して、項目のバッチを追加する。

  • 複数の UPDATE ステートメントを実行して、項目のバッチを更新する。

  • 複数の DELETE ステートメントを実行して、項目のバッチを削除する。

SDK for Go V2
注記

他にもありますGitHub。用例一覧を検索し、AWS コード例リポジトリでの設定と実行の方法を確認してください。

PartiQL ステートメントを実行できるメソッドのレシーバーである構造体を作成します。


// PartiQLRunner encapsulates the Amazon DynamoDB service actions used in the
// PartiQL examples. It contains a DynamoDB service client that is used to act on the
// specified table.
type PartiQLRunner struct {
	DynamoDbClient *dynamodb.Client
	TableName      string
}



// AddMovieBatch runs a batch of PartiQL INSERT statements to add multiple movies to the
// DynamoDB table.
func (runner PartiQLRunner) AddMovieBatch(movies []Movie) error {
	statementRequests := make([]types.BatchStatementRequest, len(movies))
	for index, movie := range movies {
		params, err := attributevalue.MarshalList([]interface{}{movie.Title, movie.Year, movie.Info})
		if err != nil {
			panic(err)
		}
		statementRequests[index] = types.BatchStatementRequest{
			Statement: aws.String(fmt.Sprintf(
				"INSERT INTO \"%v\" VALUE {'title': ?, 'year': ?, 'info': ?}", runner.TableName)),
			Parameters: params,
		}
	}

	_, err := runner.DynamoDbClient.BatchExecuteStatement(context.TODO(), &dynamodb.BatchExecuteStatementInput{
		Statements: statementRequests,
	})
	if err != nil {
		log.Printf("Couldn't insert a batch of items with PartiQL. Here's why: %v\n", err)
	}
	return err
}



// GetMovieBatch runs a batch of PartiQL SELECT statements to get multiple movies from
// the DynamoDB table by title and year.
func (runner PartiQLRunner) GetMovieBatch(movies []Movie) ([]Movie, error) {
	statementRequests := make([]types.BatchStatementRequest, len(movies))
	for index, movie := range movies {
		params, err := attributevalue.MarshalList([]interface{}{movie.Title, movie.Year})
		if err != nil {
			panic(err)
		}
		statementRequests[index] = types.BatchStatementRequest{
			Statement: aws.String(
				fmt.Sprintf("SELECT * FROM \"%v\" WHERE title=? AND year=?", runner.TableName)),
			Parameters: params,
		}
	}

	output, err := runner.DynamoDbClient.BatchExecuteStatement(context.TODO(), &dynamodb.BatchExecuteStatementInput{
		Statements: statementRequests,
	})
	var outMovies []Movie
	if err != nil {
		log.Printf("Couldn't get a batch of items with PartiQL. Here's why: %v\n", err)
	} else {
		for _, response := range output.Responses {
			var movie Movie
			err = attributevalue.UnmarshalMap(response.Item, &movie)
			if err != nil {
				log.Printf("Couldn't unmarshal response. Here's why: %v\n", err)
			} else {
				outMovies = append(outMovies, movie)
			}
		}
	}
	return outMovies, err
}



// GetAllMovies runs a PartiQL SELECT statement to get all movies from the DynamoDB table.
// The results are projected to return only the title and rating of each movie.
func (runner PartiQLRunner) GetAllMovies() ([]map[string]interface{}, error) {
	var output []map[string]interface{}
	response, err := runner.DynamoDbClient.ExecuteStatement(context.TODO(), &dynamodb.ExecuteStatementInput{
		Statement: aws.String(
			fmt.Sprintf("SELECT title, info.rating FROM \"%v\"", runner.TableName)),
	})
	if err != nil {
		log.Printf("Couldn't get movies. Here's why: %v\n", err)
	} else {
		err = attributevalue.UnmarshalListOfMaps(response.Items, &output)
		if err != nil {
			log.Printf("Couldn't unmarshal response. Here's why: %v\n", err)
		}
	}
	return output, err
}



// UpdateMovieBatch runs a batch of PartiQL UPDATE statements to update the rating of
// multiple movies that already exist in the DynamoDB table.
func (runner PartiQLRunner) UpdateMovieBatch(movies []Movie, ratings []float64) error {
	statementRequests := make([]types.BatchStatementRequest, len(movies))
	for index, movie := range movies {
		params, err := attributevalue.MarshalList([]interface{}{ratings[index], movie.Title, movie.Year})
		if err != nil {
			panic(err)
		}
		statementRequests[index] = types.BatchStatementRequest{
			Statement: aws.String(
				fmt.Sprintf("UPDATE \"%v\" SET info.rating=? WHERE title=? AND year=?", runner.TableName)),
			Parameters: params,
		}
	}

	_, err := runner.DynamoDbClient.BatchExecuteStatement(context.TODO(), &dynamodb.BatchExecuteStatementInput{
		Statements: statementRequests,
	})
	if err != nil {
		log.Printf("Couldn't update the batch of movies. Here's why: %v\n", err)
	}
	return err
}



// DeleteMovieBatch runs a batch of PartiQL DELETE statements to remove multiple movies
// from the DynamoDB table.
func (runner PartiQLRunner) DeleteMovieBatch(movies []Movie) error {
	statementRequests := make([]types.BatchStatementRequest, len(movies))
	for index, movie := range movies {
		params, err := attributevalue.MarshalList([]interface{}{movie.Title, movie.Year})
		if err != nil {
			panic(err)
		}
		statementRequests[index] = types.BatchStatementRequest{
			Statement: aws.String(
				fmt.Sprintf("DELETE FROM \"%v\" WHERE title=? AND year=?", runner.TableName)),
			Parameters: params,
		}
	}

	_, err := runner.DynamoDbClient.BatchExecuteStatement(context.TODO(), &dynamodb.BatchExecuteStatementInput{
		Statements: statementRequests,
	})
	if err != nil {
		log.Printf("Couldn't delete the batch of movies. Here's why: %v\n", err)
	}
	return err
}

テーブルを作成し、PartiQL クエリのバッチを実行するシナリオを実行します。


// RunPartiQLBatchScenario shows you how to use the AWS SDK for Go
// to run batches of PartiQL statements to query a table that stores data about movies.
//
// * Use batches of PartiQL statements to add, get, update, and delete data for
//   individual movies.
//
// This example creates an Amazon DynamoDB service client from the specified sdkConfig so that
// you can replace it with a mocked or stubbed config for unit testing.
//
// This example creates and deletes a DynamoDB table to use during the scenario.
func RunPartiQLBatchScenario(sdkConfig aws.Config, tableName string) {
	defer func() {
		if r := recover(); r != nil {
			fmt.Printf("Something went wrong with the demo.")
		}
	}()

	log.Println(strings.Repeat("-", 88))
	log.Println("Welcome to the Amazon DynamoDB PartiQL batch demo.")
	log.Println(strings.Repeat("-", 88))

	tableBasics := actions.TableBasics{
		DynamoDbClient: dynamodb.NewFromConfig(sdkConfig),
		TableName:      tableName,
	}
	runner := actions.PartiQLRunner{
		DynamoDbClient: dynamodb.NewFromConfig(sdkConfig),
		TableName:      tableName,
	}

	exists, err := tableBasics.TableExists()
	if err != nil {
		panic(err)
	}
	if !exists {
		log.Printf("Creating table %v...\n", tableName)
		_, err = tableBasics.CreateMovieTable()
		if err != nil {
			panic(err)
		} else {
			log.Printf("Created table %v.\n", tableName)
		}
	} else {
		log.Printf("Table %v already exists.\n", tableName)
	}
	log.Println(strings.Repeat("-", 88))

	currentYear, _, _ := time.Now().Date()
	customMovies := []actions.Movie{{
		Title: "House PartiQL",
		Year:  currentYear - 5,
		Info: map[string]interface{}{
			"plot":   "Wacky high jinks result from querying a mysterious database.",
			"rating": 8.5}}, {
		Title: "House PartiQL 2",
		Year:  currentYear - 3,
		Info: map[string]interface{}{
			"plot":   "Moderate high jinks result from querying another mysterious database.",
			"rating": 6.5}}, {
		Title: "House PartiQL 3",
		Year:  currentYear - 1,
		Info: map[string]interface{}{
			"plot":   "Tepid high jinks result from querying yet another mysterious database.",
			"rating": 2.5},
	},
	}

	log.Printf("Inserting a batch of movies into table '%v'.\n", tableName)
	err = runner.AddMovieBatch(customMovies)
	if err == nil {
		log.Printf("Added %v movies to the table.\n", len(customMovies))
	}
	log.Println(strings.Repeat("-", 88))

	log.Println("Getting data for a batch of movies.")
	movies, err := runner.GetMovieBatch(customMovies)
	if err == nil {
		for _, movie := range movies {
			log.Println(movie)
		}
	}
	log.Println(strings.Repeat("-", 88))

	newRatings := []float64{7.7, 4.4, 1.1}
	log.Println("Updating a batch of movies with new ratings.")
	err = runner.UpdateMovieBatch(customMovies, newRatings)
	if err == nil {
		log.Printf("Updated %v movies with new ratings.\n", len(customMovies))
	}
	log.Println(strings.Repeat("-", 88))

	log.Println("Getting projected data from the table to verify our update.")
	projections, err := runner.GetAllMovies()
	if err == nil {
		for _, projection := range projections {
			log.Println(projection)
		}
	}
	log.Println(strings.Repeat("-", 88))

	log.Println("Deleting a batch of movies.")
	err = runner.DeleteMovieBatch(customMovies)
	if err == nil {
		log.Printf("Deleted %v movies.\n", len(customMovies))
	}

	err = tableBasics.DeleteTable()
	if err == nil {
		log.Printf("Deleted table %v.\n", tableBasics.TableName)
	}

	log.Println(strings.Repeat("-", 88))
	log.Println("Thanks for watching!")
	log.Println(strings.Repeat("-", 88))
}

  • API の詳細については、AWS SDK for GoAPI BatchExecuteStatementリファレンスのを参照してください。

次のコード例は、以下の操作方法を示しています。

  • SELECT ステートメントを実行して項目を取得する。

  • INSERT 文を実行して項目を追加する。

  • UPDATE ステートメントを使用して項目を更新する。

  • DELETE ステートメントを実行して項目を削除する。

SDK for Go V2
注記

他にもありますGitHub。用例一覧を検索し、AWS コード例リポジトリでの設定と実行の方法を確認してください。

PartiQL ステートメントを実行できるメソッドのレシーバーである構造体を作成します。


// PartiQLRunner encapsulates the Amazon DynamoDB service actions used in the
// PartiQL examples. It contains a DynamoDB service client that is used to act on the
// specified table.
type PartiQLRunner struct {
	DynamoDbClient *dynamodb.Client
	TableName      string
}



// AddMovie runs a PartiQL INSERT statement to add a movie to the DynamoDB table.
func (runner PartiQLRunner) AddMovie(movie Movie) error {
	params, err := attributevalue.MarshalList([]interface{}{movie.Title, movie.Year, movie.Info})
	if err != nil {
		panic(err)
	}
	_, err = runner.DynamoDbClient.ExecuteStatement(context.TODO(), &dynamodb.ExecuteStatementInput{
		Statement: aws.String(
			fmt.Sprintf("INSERT INTO \"%v\" VALUE {'title': ?, 'year': ?, 'info': ?}",
				runner.TableName)),
		Parameters: params,
	})
	if err != nil {
		log.Printf("Couldn't insert an item with PartiQL. Here's why: %v\n", err)
	}
	return err
}



// GetMovie runs a PartiQL SELECT statement to get a movie from the DynamoDB table by
// title and year.
func (runner PartiQLRunner) GetMovie(title string, year int) (Movie, error) {
	var movie Movie
	params, err := attributevalue.MarshalList([]interface{}{title, year})
	if err != nil {
		panic(err)
	}
	response, err := runner.DynamoDbClient.ExecuteStatement(context.TODO(), &dynamodb.ExecuteStatementInput{
		Statement: aws.String(
			fmt.Sprintf("SELECT * FROM \"%v\" WHERE title=? AND year=?",
				runner.TableName)),
		Parameters: params,
	})
	if err != nil {
		log.Printf("Couldn't get info about %v. Here's why: %v\n", title, err)
	} else {
		err = attributevalue.UnmarshalMap(response.Items[0], &movie)
		if err != nil {
			log.Printf("Couldn't unmarshal response. Here's why: %v\n", err)
		}
	}
	return movie, err
}



// UpdateMovie runs a PartiQL UPDATE statement to update the rating of a movie that
// already exists in the DynamoDB table.
func (runner PartiQLRunner) UpdateMovie(movie Movie, rating float64) error {
	params, err := attributevalue.MarshalList([]interface{}{rating, movie.Title, movie.Year})
	if err != nil {
		panic(err)
	}
	_, err = runner.DynamoDbClient.ExecuteStatement(context.TODO(), &dynamodb.ExecuteStatementInput{
		Statement: aws.String(
			fmt.Sprintf("UPDATE \"%v\" SET info.rating=? WHERE title=? AND year=?",
				runner.TableName)),
		Parameters: params,
	})
	if err != nil {
		log.Printf("Couldn't update movie %v. Here's why: %v\n", movie.Title, err)
	}
	return err
}



// DeleteMovie runs a PartiQL DELETE statement to remove a movie from the DynamoDB table.
func (runner PartiQLRunner) DeleteMovie(movie Movie) error {
	params, err := attributevalue.MarshalList([]interface{}{movie.Title, movie.Year})
	if err != nil {
		panic(err)
	}
	_, err = runner.DynamoDbClient.ExecuteStatement(context.TODO(), &dynamodb.ExecuteStatementInput{
		Statement: aws.String(
			fmt.Sprintf("DELETE FROM \"%v\" WHERE title=? AND year=?",
				runner.TableName)),
		Parameters: params,
	})
	if err != nil {
		log.Printf("Couldn't delete %v from the table. Here's why: %v\n", movie.Title, err)
	}
	return err
}

テーブルを作成し、PartiQL クエリを実行するシナリオを実行します。


// RunPartiQLSingleScenario shows you how to use the AWS SDK for Go
// to use PartiQL to query a table that stores data about movies.
//
// * Use PartiQL statements to add, get, update, and delete data for individual movies.
//
// This example creates an Amazon DynamoDB service client from the specified sdkConfig so that
// you can replace it with a mocked or stubbed config for unit testing.
//
// This example creates and deletes a DynamoDB table to use during the scenario.
func RunPartiQLSingleScenario(sdkConfig aws.Config, tableName string) {
	defer func() {
		if r := recover(); r != nil {
			fmt.Printf("Something went wrong with the demo.")
		}
	}()

	log.Println(strings.Repeat("-", 88))
	log.Println("Welcome to the Amazon DynamoDB PartiQL single action demo.")
	log.Println(strings.Repeat("-", 88))

	tableBasics := actions.TableBasics{
		DynamoDbClient: dynamodb.NewFromConfig(sdkConfig),
		TableName:      tableName,
	}
	runner := actions.PartiQLRunner{
		DynamoDbClient: dynamodb.NewFromConfig(sdkConfig),
		TableName:      tableName,
	}

	exists, err := tableBasics.TableExists()
	if err != nil {
		panic(err)
	}
	if !exists {
		log.Printf("Creating table %v...\n", tableName)
		_, err = tableBasics.CreateMovieTable()
		if err != nil {
			panic(err)
		} else {
			log.Printf("Created table %v.\n", tableName)
		}
	} else {
		log.Printf("Table %v already exists.\n", tableName)
	}
	log.Println(strings.Repeat("-", 88))

	currentYear, _, _ := time.Now().Date()
	customMovie := actions.Movie{
		Title: "24 Hour PartiQL People",
		Year:  currentYear,
		Info: map[string]interface{}{
			"plot":   "A group of data developers discover a new query language they can't stop using.",
			"rating": 9.9,
		},
	}

	log.Printf("Inserting movie '%v' released in %v.", customMovie.Title, customMovie.Year)
	err = runner.AddMovie(customMovie)
	if err == nil {
		log.Printf("Added %v to the movie table.\n", customMovie.Title)
	}
	log.Println(strings.Repeat("-", 88))

	log.Printf("Getting data for movie '%v' released in %v.", customMovie.Title, customMovie.Year)
	movie, err := runner.GetMovie(customMovie.Title, customMovie.Year)
	if err == nil {
		log.Println(movie)
	}
	log.Println(strings.Repeat("-", 88))

	newRating := 6.6
	log.Printf("Updating movie '%v' with a rating of %v.", customMovie.Title, newRating)
	err = runner.UpdateMovie(customMovie, newRating)
	if err == nil {
		log.Printf("Updated %v with a new rating.\n", customMovie.Title)
	}
	log.Println(strings.Repeat("-", 88))

	log.Printf("Getting data again to verify the update.")
	movie, err = runner.GetMovie(customMovie.Title, customMovie.Year)
	if err == nil {
		log.Println(movie)
	}
	log.Println(strings.Repeat("-", 88))

	log.Printf("Deleting movie '%v'.\n", customMovie.Title)
	err = runner.DeleteMovie(customMovie)
	if err == nil {
		log.Printf("Deleted %v.\n", customMovie.Title)
	}

	err = tableBasics.DeleteTable()
	if err == nil {
		log.Printf("Deleted table %v.\n", tableBasics.TableName)
	}

	log.Println(strings.Repeat("-", 88))
	log.Println("Thanks for watching!")
	log.Println(strings.Repeat("-", 88))
}

  • API の詳細については、AWS SDK for GoAPI ExecuteStatementリファレンスのを参照してください。