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
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; } } }