範例CRUD：使用 AWS SDK for .NET 對象持久性模型

下列 C# 程式碼範例會宣告具有 Id、Title、Isbn 和 BookAuthors 屬性的 Book 類別。範例會使用物件持久性屬性，將這些屬性映射至 Amazon DynamoDB 中的 ProductCatalog 資料表。然後，範例會使用 D ynamoDBContext 類別來說明典型的建立、讀取、更新和 delete (CRUD) 作業。此範例會建立範例Book instance並將其儲存至ProductCatalog表格中。它會接著擷取書籍項目並更新其 Isbn 和 BookAuthors 屬性。請注意，更新會取代現有的作者清單。最後，該範例會刪除書籍項目。

如需此範例中所使用 ProductCatalog 資料表的詳細資訊，請參閱 在 DynamoDB 中建立資料表，以及載入程式碼範例的資料。如需測試下列範例的 step-by-step 指示，請參閱。 NET程式碼範例。

注意

下列範例無法使用。 NET核心，因為它不支持同步方法。如需詳細資訊，請參閱 AWS 非同步APIs的. NET。

範例 CRUD使用 D ynamoDBContext 類的操作

    /// <summary>
    /// Shows how to perform high-level CRUD operations on an Amazon DynamoDB
    /// table.
    /// </summary>
    public class HighLevelItemCrud
    {
        public static async Task Main()
        {
            var client = new AmazonDynamoDBClient();
            DynamoDBContext context = new DynamoDBContext(client);
            await PerformCRUDOperations(context);
        }

        public static async Task PerformCRUDOperations(IDynamoDBContext 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 to the ProductCatalog table.
            await context.SaveAsync(myBook);

            // Retrieve the book from the ProductCatalog table.
            Book bookRetrieved = await context.LoadAsync<Book>(bookId);

            // Update some properties.
            bookRetrieved.Isbn = "222-2222221001";

            // Update existing authors list with the following values.
            bookRetrieved.BookAuthors = new List<string> { " Author 1", "Author x" };
            await context.SaveAsync(bookRetrieved);

            // Retrieve the updated book. This time, add the optional
            // ConsistentRead parameter using DynamoDBContextConfig object.
            await context.LoadAsync<Book>(bookId, new DynamoDBContextConfig
            {
                ConsistentRead = true,
            });

            // Delete the book.
            await context.DeleteAsync<Book>(bookId);

            // Try to retrieve deleted book. It should return null.
            Book deletedBook = await context.LoadAsync<Book>(bookId, new DynamoDBContextConfig
            {
                ConsistentRead = true,
            });

            if (deletedBook == null)
            {
                Console.WriteLine("Book is deleted");
            }
        }
    }

範例

要新增至表 ProductCatalog 格的圖書課程資訊

    /// <summary>
    /// A class representing book information to be added to the Amazon DynamoDB
    /// ProductCatalog table.
    /// </summary>
    [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; }
    }