AWS SDK を使用して DynamoDB のドキュメントモデルを使用する - AWSSDK コードサンプル

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AWS SDK を使用して DynamoDB のドキュメントモデルを使用する

次のコード例は、DynamoDB のドキュメントモデルと AWS SDK を使用して、作成、読み込み、更新、削除 (CRUD) オペレーションとバッチオペレーションを実行する方法を示しています。

詳細については、「ドキュメントモデル」を参照してください。

.NET
AWS SDK for .NET
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。

ドキュメントモデルを使用して CRUD オペレーションを実行します。

/// <summary> /// Performs CRUD operations on an Amazon DynamoDB table. The example was /// created using the AWS SDK for .NET 3.7 and .NET Core 5.0. /// </summary> public class MidlevelItemCRUD { public static async Task Main() { var tableName = "ProductCatalog"; var sampleBookId = 555; var client = new AmazonDynamoDBClient(); var productCatalog = LoadTable(client, tableName); await CreateBookItem(productCatalog, sampleBookId); RetrieveBook(productCatalog, sampleBookId); // Couple of sample updates. UpdateMultipleAttributes(productCatalog, sampleBookId); UpdateBookPriceConditionally(productCatalog, sampleBookId); // Delete. await DeleteBook(productCatalog, sampleBookId); } /// <summary> /// Loads the contents of a DynamoDB table. /// </summary> /// <param name="client">An initialized DynamoDB client object.</param> /// <param name="tableName">The name of the table to load.</param> /// <returns>A DynamoDB table object.</returns> public static Table LoadTable(IAmazonDynamoDB client, string tableName) { Table productCatalog = Table.LoadTable(client, tableName); return productCatalog; } /// <summary> /// Creates an example book item and adds it to the DynamoDB table /// ProductCatalog. /// </summary> /// <param name="productCatalog">A DynamoDB table object.</param> /// <param name="sampleBookId">An integer value representing the book's ID.</param> public static async Task CreateBookItem(Table productCatalog, int sampleBookId) { Console.WriteLine("\n*** Executing CreateBookItem() ***"); var book = new Document { ["Id"] = sampleBookId, ["Title"] = "Book " + sampleBookId, ["Price"] = 19.99, ["ISBN"] = "111-1111111111", ["Authors"] = new List<string> { "Author 1", "Author 2", "Author 3" }, ["PageCount"] = 500, ["Dimensions"] = "8.5x11x.5", ["InPublication"] = new DynamoDBBool(true), ["InStock"] = new DynamoDBBool(false), ["QuantityOnHand"] = 0, }; // Adds the book to the ProductCatalog table. await productCatalog.PutItemAsync(book); } /// <summary> /// Retrieves an item, a book, from the DynamoDB ProductCatalog table. /// </summary> /// <param name="productCatalog">A DynamoDB table object.</param> /// <param name="sampleBookId">An integer value representing the book's ID.</param> public static async void RetrieveBook( Table productCatalog, int sampleBookId) { Console.WriteLine("\n*** Executing RetrieveBook() ***"); // Optional configuration. var config = new GetItemOperationConfig { AttributesToGet = new List<string> { "Id", "ISBN", "Title", "Authors", "Price" }, ConsistentRead = true, }; Document document = await productCatalog.GetItemAsync(sampleBookId, config); Console.WriteLine("RetrieveBook: Printing book retrieved..."); PrintDocument(document); } /// <summary> /// Updates multiple attributes for a book and writes the changes to the /// DynamoDB table ProductCatalog. /// </summary> /// <param name="productCatalog">A DynamoDB table object.</param> /// <param name="sampleBookId">An integer value representing the book's ID.</param> public static async void UpdateMultipleAttributes( Table productCatalog, int sampleBookId) { Console.WriteLine("\nUpdating multiple attributes...."); int partitionKey = sampleBookId; var book = new Document { ["Id"] = partitionKey, // List of attribute updates. // The following replaces the existing authors list. ["Authors"] = new List<string> { "Author x", "Author y" }, ["newAttribute"] = "New Value", ["ISBN"] = null, // Remove it. }; // Optional parameters. var config = new UpdateItemOperationConfig { // Gets updated item in response. ReturnValues = ReturnValues.AllNewAttributes, }; Document updatedBook = await productCatalog.UpdateItemAsync(book, config); Console.WriteLine("UpdateMultipleAttributes: Printing item after updates ..."); PrintDocument(updatedBook); } /// <summary> /// Updates a book item if it meets the specified criteria. /// </summary> /// <param name="productCatalog">A DynamoDB table object.</param> /// <param name="sampleBookId">An integer value representing the book's ID.</param> public static async void UpdateBookPriceConditionally( Table productCatalog, int sampleBookId) { Console.WriteLine("\n*** Executing UpdateBookPriceConditionally() ***"); int partitionKey = sampleBookId; var book = new Document { ["Id"] = partitionKey, ["Price"] = 29.99, }; // For conditional price update, creating a condition expression. var expr = new Expression { ExpressionStatement = "Price = :val", }; expr.ExpressionAttributeValues[":val"] = 19.00; // Optional parameters. var config = new UpdateItemOperationConfig { ConditionalExpression = expr, ReturnValues = ReturnValues.AllNewAttributes, }; Document updatedBook = await productCatalog.UpdateItemAsync(book, config); Console.WriteLine("UpdateBookPriceConditionally: Printing item whose price was conditionally updated"); PrintDocument(updatedBook); } /// <summary> /// Deletes the book with the supplied Id value from the DynamoDB table /// ProductCatalog. /// </summary> /// <param name="productCatalog">A DynamoDB table object.</param> /// <param name="sampleBookId">An integer value representing the book's ID.</param> public static async Task DeleteBook( Table productCatalog, int sampleBookId) { Console.WriteLine("\n*** Executing DeleteBook() ***"); // Optional configuration. var config = new DeleteItemOperationConfig { // Returns the deleted item. ReturnValues = ReturnValues.AllOldAttributes, }; Document document = await productCatalog.DeleteItemAsync(sampleBookId, config); Console.WriteLine("DeleteBook: Printing deleted just deleted..."); PrintDocument(document); } /// <summary> /// Prints the information for the supplied DynamoDB document. /// </summary> /// <param name="updatedDocument">A DynamoDB document object.</param> public static void PrintDocument(Document updatedDocument) { if (updatedDocument is null) { return; } foreach (var attribute in updatedDocument.GetAttributeNames()) { string stringValue = null; var value = updatedDocument[attribute]; if (value is null) { continue; } if (value is Primitive) { stringValue = value.AsPrimitive().Value.ToString(); } else if (value is PrimitiveList) { stringValue = string.Join(",", (from primitive in value.AsPrimitiveList().Entries select primitive.Value).ToArray()); } Console.WriteLine($"{attribute} - {stringValue}", attribute, stringValue); } } }

ドキュメントモデルを使用してバッチ書き込みオペレーションを実行します。

/// <summary> /// Shows how to use mid-level Amazon DynamoDB API calls to perform batch /// operations. The example was created using the AWS SDK for .NET version /// 3.7 and .NET Core 5.0. /// </summary> public class MidLevelBatchWriteItem { public static async Task Main() { IAmazonDynamoDB client = new AmazonDynamoDBClient(); await SingleTableBatchWrite(client); await MultiTableBatchWrite(client); } /// <summary> /// Perform a batch operation on a single DynamoDB table. /// </summary> /// <param name="client">An initialized DynamoDB object.</param> public static async Task SingleTableBatchWrite(IAmazonDynamoDB client) { Table productCatalog = Table.LoadTable(client, "ProductCatalog"); var batchWrite = productCatalog.CreateBatchWrite(); var book1 = new Document { ["Id"] = 902, ["Title"] = "My book1 in batch write using .NET helper classes", ["ISBN"] = "902-11-11-1111", ["Price"] = 10, ["ProductCategory"] = "Book", ["Authors"] = new List<string> { "Author 1", "Author 2", "Author 3" }, ["Dimensions"] = "8.5x11x.5", ["InStock"] = new DynamoDBBool(true), ["QuantityOnHand"] = new DynamoDBNull(), // Quantity is unknown at this time. }; batchWrite.AddDocumentToPut(book1); // Specify delete item using overload that takes PK. batchWrite.AddKeyToDelete(12345); Console.WriteLine("Performing batch write in SingleTableBatchWrite()"); await batchWrite.ExecuteAsync(); } /// <summary> /// Perform a batch operation involving multiple DynamoDB tables. /// </summary> /// <param name="client">An initialized DynamoDB client object.</param> public static async Task MultiTableBatchWrite(IAmazonDynamoDB client) { // Specify item to add in the Forum table. Table forum = Table.LoadTable(client, "Forum"); var forumBatchWrite = forum.CreateBatchWrite(); var forum1 = new Document { ["Name"] = "Test BatchWrite Forum", ["Threads"] = 0, }; forumBatchWrite.AddDocumentToPut(forum1); // Specify item to add in the Thread table. Table thread = Table.LoadTable(client, "Thread"); var threadBatchWrite = thread.CreateBatchWrite(); var thread1 = new Document { ["ForumName"] = "S3 forum", ["Subject"] = "My sample question", ["Message"] = "Message text", ["KeywordTags"] = new List<string> { "S3", "Bucket" }, }; threadBatchWrite.AddDocumentToPut(thread1); // Specify item to delete from the Thread table. threadBatchWrite.AddKeyToDelete("someForumName", "someSubject"); // Create multi-table batch. var superBatch = new MultiTableDocumentBatchWrite(); superBatch.AddBatch(forumBatchWrite); superBatch.AddBatch(threadBatchWrite); Console.WriteLine("Performing batch write in MultiTableBatchWrite()"); // Execute the batch. await superBatch.ExecuteAsync(); } }

ドキュメントモデルを使用してテーブルをスキャンします。

/// <summary> /// Shows how to use mid-level Amazon DynamoDB API calls to scan a DynamoDB /// table for values. This example was created using the AWS SDK for .NET /// version 3.7 and .NET Core 5.0. /// </summary> public class MidLevelScanOnly { public static async Task Main() { IAmazonDynamoDB client = new AmazonDynamoDBClient(); Table productCatalogTable = Table.LoadTable(client, "ProductCatalog"); await FindProductsWithNegativePrice(productCatalogTable); await FindProductsWithNegativePriceWithConfig(productCatalogTable); } /// <summary> /// Retrieves any products that have a negative price in a DynamoDB table. /// </summary> /// <param name="productCatalogTable">A DynamoDB table object.</param> public static async Task FindProductsWithNegativePrice( Table productCatalogTable) { // Assume there is a price error. So we scan to find items priced < 0. var scanFilter = new ScanFilter(); scanFilter.AddCondition("Price", ScanOperator.LessThan, 0); Search search = productCatalogTable.Scan(scanFilter); do { var documentList = await search.GetNextSetAsync(); Console.WriteLine("\nFindProductsWithNegativePrice: printing ............"); foreach (var document in documentList) { PrintDocument(document); } } while (!search.IsDone); } /// <summary> /// Finds any items in the ProductCatalog table using a DynamoDB /// configuration object. /// </summary> /// <param name="productCatalogTable">A DynamoDB table object.</param> public static async Task FindProductsWithNegativePriceWithConfig( Table productCatalogTable) { // Assume there is a price error. So we scan to find items priced < 0. var scanFilter = new ScanFilter(); scanFilter.AddCondition("Price", ScanOperator.LessThan, 0); var config = new ScanOperationConfig() { Filter = scanFilter, Select = SelectValues.SpecificAttributes, AttributesToGet = new List<string> { "Title", "Id" }, }; Search search = productCatalogTable.Scan(config); do { var documentList = await search.GetNextSetAsync(); Console.WriteLine("\nFindProductsWithNegativePriceWithConfig: printing ............"); foreach (var document in documentList) { PrintDocument(document); } } while (!search.IsDone); } /// <summary> /// Displays the details of the passed DynamoDB document object on the /// console. /// </summary> /// <param name="document">A DynamoDB document object.</param> public static void PrintDocument(Document document) { Console.WriteLine(); foreach (var attribute in document.GetAttributeNames()) { string stringValue = null; var value = document[attribute]; if (value is Primitive) { stringValue = value.AsPrimitive().Value.ToString(); } else if (value is PrimitiveList) { stringValue = string.Join(",", (from primitive in value.AsPrimitiveList().Entries select primitive.Value).ToArray()); } Console.WriteLine($"{attribute} - {stringValue}"); } } }

ドキュメントモデルを使用して、テーブルをクエリおよびスキャンする。

/// <summary> /// Shows how to perform mid-level query procedures on an Amazon DynamoDB /// table. The example was created using the AWS SDK for .NET version 3.7 and /// .NET Core 5.0. /// </summary> public class MidLevelQueryAndScan { public static async Task Main() { IAmazonDynamoDB client = new AmazonDynamoDBClient(); // Query examples. Table replyTable = Table.LoadTable(client, "Reply"); string forumName = "Amazon DynamoDB"; string threadSubject = "DynamoDB Thread 2"; await FindRepliesInLast15Days(replyTable); await FindRepliesInLast15DaysWithConfig(replyTable, forumName, threadSubject); await FindRepliesPostedWithinTimePeriod(replyTable, forumName, threadSubject); // Get Example. Table productCatalogTable = Table.LoadTable(client, "ProductCatalog"); int productId = 101; await GetProduct(productCatalogTable, productId); } /// <summary> /// Retrieves information about a product from the DynamoDB table /// ProductCatalog based on the product ID and displays the information /// on the console. /// </summary> /// <param name="tableName">The name of the table from which to retrieve /// product information.</param> /// <param name="productId">The ID of the product to retrieve.</param> public static async Task GetProduct(Table tableName, int productId) { Console.WriteLine("*** Executing GetProduct() ***"); Document productDocument = await tableName.GetItemAsync(productId); if (productDocument != null) { PrintDocument(productDocument); } else { Console.WriteLine("Error: product " + productId + " does not exist"); } } /// <summary> /// Retrieves replies from the passed DynamoDB table object. /// </summary> /// <param name="table">The table we want to query.</param> public static async Task FindRepliesInLast15Days( Table table) { DateTime twoWeeksAgoDate = DateTime.UtcNow - TimeSpan.FromDays(15); var filter = new QueryFilter("Id", QueryOperator.Equal, "Id"); filter.AddCondition("ReplyDateTime", QueryOperator.GreaterThan, twoWeeksAgoDate); // Use Query overloads that take the minimum required query parameters. Search search = table.Query(filter); do { var documentSet = await search.GetNextSetAsync(); Console.WriteLine("\nFindRepliesInLast15Days: printing ............"); foreach (var document in documentSet) { PrintDocument(document); } } while (!search.IsDone); } /// <summary> /// Retrieve replies made during a specific time period. /// </summary> /// <param name="table">The table we want to query.</param> /// <param name="forumName">The name of the forum that we're interested in.</param> /// <param name="threadSubject">The subject of the thread, which we are /// searching for replies.</param> public static async Task FindRepliesPostedWithinTimePeriod( Table table, string forumName, string threadSubject) { DateTime startDate = DateTime.UtcNow.Subtract(new TimeSpan(21, 0, 0, 0)); DateTime endDate = DateTime.UtcNow.Subtract(new TimeSpan(1, 0, 0, 0)); var filter = new QueryFilter("Id", QueryOperator.Equal, forumName + "#" + threadSubject); filter.AddCondition("ReplyDateTime", QueryOperator.Between, startDate, endDate); var config = new QueryOperationConfig() { Limit = 2, // 2 items/page. Select = SelectValues.SpecificAttributes, AttributesToGet = new List<string> { "Message", "ReplyDateTime", "PostedBy", }, ConsistentRead = true, Filter = filter, }; Search search = table.Query(config); do { var documentList = await search.GetNextSetAsync(); Console.WriteLine("\nFindRepliesPostedWithinTimePeriod: printing replies posted within dates: {0} and {1} ............", startDate, endDate); foreach (var document in documentList) { PrintDocument(document); } } while (!search.IsDone); } /// <summary> /// Perform a query for replies made in the last 15 days using a DynamoDB /// QueryOperationConfig object. /// </summary> /// <param name="table">The table we want to query.</param> /// <param name="forumName">The name of the forum that we're interested in.</param> /// <param name="threadName">The bane of the thread that we are searching /// for replies.</param> public static async Task FindRepliesInLast15DaysWithConfig( Table table, string forumName, string threadName) { DateTime twoWeeksAgoDate = DateTime.UtcNow - TimeSpan.FromDays(15); var filter = new QueryFilter("Id", QueryOperator.Equal, forumName + "#" + threadName); filter.AddCondition("ReplyDateTime", QueryOperator.GreaterThan, twoWeeksAgoDate); var config = new QueryOperationConfig() { Filter = filter, // Optional parameters. Select = SelectValues.SpecificAttributes, AttributesToGet = new List<string> { "Message", "ReplyDateTime", "PostedBy", }, ConsistentRead = true, }; Search search = table.Query(config); do { var documentSet = await search.GetNextSetAsync(); Console.WriteLine("\nFindRepliesInLast15DaysWithConfig: printing ............"); foreach (var document in documentSet) { PrintDocument(document); } } while (!search.IsDone); } /// <summary> /// Displays the contents of the passed DynamoDB document on the console. /// </summary> /// <param name="document">A DynamoDB document to display.</param> public static void PrintDocument(Document document) { Console.WriteLine(); foreach (var attribute in document.GetAttributeNames()) { string stringValue = null; var value = document[attribute]; if (value is Primitive) { stringValue = value.AsPrimitive().Value.ToString(); } else if (value is PrimitiveList) { stringValue = string.Join(",", (from primitive in value.AsPrimitiveList().Entries select primitive.Value).ToArray()); } Console.WriteLine($"{attribute} - {stringValue}"); } } }