Amazon DynamoDB
开发人员指南 (API 版本 2012-08-10)
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步骤 4:将新电影添加到 Movies 表

Microsoft .NET 和 DynamoDB 教程的本步骤中,您将向 Amazon DynamoDB 中的 Movies 表添加一个新电影记录。DynamoDB_intro 中的 Main 函数首先创建一个 DynamoDB 文档模型 Document,然后等待 WritingNewMovie_async,该函数在 04_WritingNewItem.cs 文件中实现。

/** * Copyright 2010-2019, 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 * * * * 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.Threading.Tasks; using Amazon.DynamoDBv2.DocumentModel; namespace DynamoDB_intro { public static partial class Ddb_Intro { /*-------------------------------------------------------------------------- * WritingNewMovie *--------------------------------------------------------------------------*/ public static async Task WritingNewMovie_async( Document newItem ) { operationSucceeded = false; operationFailed = false; int year = (int) newItem["year"]; string name = newItem["title"]; if( await ReadingMovie_async( year, name, false ) ) Console.WriteLine( " The {0} movie \"{1}\" is already in the Movies table...\n" + " -- No need to add it again... its info is as follows:\n{2}", year, name, movie_record.ToJsonPretty( ) ); else { try { Task<Document> writeNew = moviesTable.PutItemAsync(newItem, token); Console.WriteLine(" -- Writing a new movie to the Movies table..."); await writeNew; Console.WriteLine(" -- Wrote the item successfully!"); operationSucceeded = true; } catch (Exception ex) { Console.WriteLine(" FAILED to write the new movie, because:\n {0}.", ex.Message); operationFailed = true; } } } }

WritingNewMovie_async 首先检查确定新电影是否已添加到 Movies 表。如果没有,它将等待 DynamoDB Table.PutItemAsyn 方法添加新电影记录。



步骤 5:从 Movies 表中读取并显示一个记录