using System;

using System.Collections.Generic;

using System.Linq;

​

​

​

    class MidlevelItemCRUD

    {

        private static string tableName = "P";

        // The sample uses the following id PK value to add book item.

        private static int sampleBookId = 555;

​

        static void Main(string[] args)

        {

            try

            {

                CATEGORIA_PRODUCTOS = Table.LoadTable(client, tableName);

                CreateBookItem(productCatalog);

                RetrieveBook(productCatalog);

                // Couple of sample updates.

                UpdateMultipleAttributes(productCatalog);

                UpdateBookPriceConditionally(productCatalog);

​

                // Delete.

                DeleteBook(productCatalog);

                Console.WriteLine("To continue, press Enter");

                Console.ReadLine();

            }

            catch (Exception e) { Console.WriteLine(e.Message); }

        }

​

        // Creates a sample book item.

        private static void CreateBookItem(Table productCatalog)

        {

            Console.WriteLine("\n*** Executing CreateBookItem() ***");

            var book = new Document();

            book["Id"] = sampleBookId;

            book["Title"] = "Book " + sampleBookId;

            book["Price"] = 19.99;

            book["ISBN"] = "111-1111111111";

            book["Authors"] = new List<string> { "Author 1", "Author 2", "Author 3" };

            book["PageCount"] = 500;

            book["Dimensions"] = "8.5x11x.5";

            book["InPublication"] = new DynamoDBBool(true);

            book["InStock"] = new DynamoDBBool(false);

            book["QuantityOnHand"] = 0;

​

            productCatalog.PutItem(book);

        }

​

        private static void RetrieveBook(Table productCatalog)

        {

            Console.WriteLine("\n*** Executing RetrieveBook() ***");

            // Optional configuration.

            GetItemOperationConfig config = new GetItemOperationConfig

            {

                AttributesToGet = new List<string> { "Id", "ISBN", "Title", "Authors", "Price" },

                ConsistentRead = true

            };

            Document document = productCatalog.GetItem(sampleBookId, config);

            Console.WriteLine("RetrieveBook: Printing book retrieved...");

            PrintDocument(document);

        }

​

        private static void UpdateMultipleAttributes(Table productCatalog)

        {

            Console.WriteLine("\n*** Executing UpdateMultipleAttributes() ***");

            Console.WriteLine("\nUpdating multiple attributes....");

            int partitionKey = sampleBookId;

​

            var book = new Document();

            book["Id"] = partitionKey;

            // List of attribute updates.

            // The following replaces the existing authors list.

            book["Authors"] = new List<string> { "Author x", "Author y" };

            book["newAttribute"] = "New Value";

            book["ISBN"] = null; // Remove it.

​

            // Optional parameters.

            UpdateItemOperationConfig config = new UpdateItemOperationConfig

            {

                // Get updated item in response.

                ReturnValues = ReturnValues.AllNewAttributes

            };

            Document updatedBook = productCatalog.UpdateItem(book, config);

            Console.WriteLine("UpdateMultipleAttributes: Printing item after updates ...");

            PrintDocument(updatedBook);

        }

​

        private static void UpdateBookPriceConditionally(Table productCatalog)

        {

            Console.WriteLine("\n*** Executing UpdateBookPriceConditionally() ***");

​

            int partitionKey = sampleBookId;

​

            var book = new Document();

            book["Id"] = partitionKey;

            book["Price"] = 29.99;

​

            // For conditional price update, creating a condition expression.

            Expression expr = new Expression();

            expr.ExpressionStatement = "Price = :val";

            expr.ExpressionAttributeValues[":val"] = 19.00;

​

            // Optional parameters.

            UpdateItemOperationConfig config = new UpdateItemOperationConfig

            {

                ConditionalExpression = expr,

                ReturnValues = ReturnValues.AllNewAttributes

            };

            Document updatedBook = productCatalog.UpdateItem(book, config);

            Console.WriteLine("UpdateBookPriceConditionally: Printing item whose price was conditionally updated");

            PrintDocument(updatedBook);

        }

​

        private static void DeleteBook(Table productCatalog)

        {

            Console.WriteLine("\n*** Executing DeleteBook() ***");

            // Optional configuration.

            DeleteItemOperationConfig config = new DeleteItemOperationConfig

            {

                // Return the deleted item.

                ReturnValues = ReturnValues.AllOldAttributes

            };

            Document document = productCatalog.DeleteItem(sampleBookId, config);

            Console.WriteLine("DeleteBook: Printing deleted just deleted...");

            PrintDocument(document);

        }

​

        private static void PrintDocument(Document updatedDocument)

        {

            foreach (var attribute in updatedDocument.GetAttributeNames())

            {

                string stringValue = null;

                var value = updatedDocument[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("{0} - {1}", attribute, stringValue);

            }

        }

    }

}