Example: CRUD Operations Using the AWS SDK for .NET Object Persistence Model - Amazon DynamoDB

Example: CRUD Operations Using the AWS SDK for .NET Object Persistence Model

The following C# code example declares a Book class with Id, Title, ISBN, and Authors properties. The example uses object persistence attributes to map these properties to the ProductCatalog table in Amazon DynamoDB. The example then uses the DynamoDBContext to illustrate typical create, read, update, and delete (CRUD) operations. The example creates a sample Book instance and saves it to the ProductCatalog table. It then retrieves the book item and updates its ISBN and Authors properties. Note that the update replaces the existing authors list. Finally, the example deletes the book item.

For more information about the ProductCatalog table used in this example, see Creating Tables and Loading Data for Code Examples in DynamoDB. For step-by-step instructions to test the following example, see .NET Code Examples.

Note

The following example doesn't work with .NET core because it doesn't support synchronous methods. For more information, see AWS Asynchronous APIs for .NET.

Example

/** * Copyright 2010-2019 Amazon.com, Inc. or its affiliates. All Rights Reserved. * * This file is licensed under the Apache License, Version 2.0 (the "License"). * You may not use this file except in compliance with the License. A copy of * the License is located at * * http://aws.amazon.com/apache2.0/ * * This file is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR * CONDITIONS OF ANY KIND, either express or implied. See the License for the * specific language governing permissions and limitations under the License. */ using System; using System.Collections.Generic; using Amazon.DynamoDBv2; using Amazon.DynamoDBv2.DataModel; using Amazon.Runtime; namespace com.amazonaws.codesamples { class HighLevelItemCRUD { private static AmazonDynamoDBClient client = new AmazonDynamoDBClient(); static void Main(string[] args) { try { DynamoDBContext context = new DynamoDBContext(client); TestCRUDOperations(context); Console.WriteLine("To continue, press Enter"); Console.ReadLine(); } catch (AmazonDynamoDBException e) { Console.WriteLine(e.Message); } catch (AmazonServiceException e) { Console.WriteLine(e.Message); } catch (Exception e) { Console.WriteLine(e.Message); } } private static void TestCRUDOperations(DynamoDBContext context) { int bookID = 1001; // Some unique value. Book myBook = new Book { Id = bookID, Title = "object persistence-AWS SDK for.NET SDK-Book 1001", ISBN = "111-1111111001", BookAuthors = new List<string> { "Author 1", "Author 2" }, }; // Save the book. context.Save(myBook); // Retrieve the book. Book bookRetrieved = context.Load<Book>(bookID); // Update few properties. bookRetrieved.ISBN = "222-2222221001"; bookRetrieved.BookAuthors = new List<string> { " Author 1", "Author x" }; // Replace existing authors list with this. context.Save(bookRetrieved); // Retrieve the updated book. This time add the optional ConsistentRead parameter using DynamoDBContextConfig object. Book updatedBook = context.Load<Book>(bookID, new DynamoDBContextConfig { ConsistentRead = true }); // Delete the book. context.Delete<Book>(bookID); // Try to retrieve deleted book. It should return null. Book deletedBook = context.Load<Book>(bookID, new DynamoDBContextConfig { ConsistentRead = true }); if (deletedBook == null) Console.WriteLine("Book is deleted"); } } [DynamoDBTable("ProductCatalog")] public class Book { [DynamoDBHashKey] //Partition key public int Id { get; set; } [DynamoDBProperty] public string Title { get; set; } [DynamoDBProperty] public string ISBN { get; set; } [DynamoDBProperty("Authors")] //String Set datatype public List<string> BookAuthors { get; set; } } }