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MidLevelQueryAndScan.cs

/** * 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 System.Linq; using Amazon.DynamoDBv2; using Amazon.DynamoDBv2.DocumentModel; using Amazon.Runtime; using Amazon.SecurityToken; namespace com.amazonaws.codesamples { class MidLevelQueryAndScan { private static AmazonDynamoDBClient client = new AmazonDynamoDBClient(); static void Main(string[] args) { try { // Query examples. Table replyTable = Table.LoadTable(client, "Reply"); string forumName = "Amazon DynamoDB"; string threadSubject = "DynamoDB Thread 2"; FindRepliesInLast15Days(replyTable, forumName, threadSubject); FindRepliesInLast15DaysWithConfig(replyTable, forumName, threadSubject); FindRepliesPostedWithinTimePeriod(replyTable, forumName, threadSubject); // Get Example. Table productCatalogTable = Table.LoadTable(client, "ProductCatalog"); int productId = 101; GetProduct(productCatalogTable, productId); 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 GetProduct(Table tableName, int productId) { Console.WriteLine("*** Executing GetProduct() ***"); Document productDocument = tableName.GetItem(productId); if (productDocument != null) { PrintDocument(productDocument); } else { Console.WriteLine("Error: product " + productId + " does not exist"); } } private static void FindRepliesInLast15Days(Table table, string forumName, string threadSubject) { string Attribute = forumName + "#" + threadSubject; DateTime twoWeeksAgoDate = DateTime.UtcNow - TimeSpan.FromDays(15); QueryFilter filter = new QueryFilter("Id", QueryOperator.Equal, partitionKey); filter.AddCondition("ReplyDateTime", QueryOperator.GreaterThan, twoWeeksAgoDate); // Use Query overloads that takes the minimum required query parameters. Search search = table.Query(filter); List<Document> documentSet = new List<Document>(); do { documentSet = search.GetNextSet(); Console.WriteLine("\nFindRepliesInLast15Days: printing ............"); foreach (var document in documentSet) PrintDocument(document); } while (!search.IsDone); } private static void FindRepliesPostedWithinTimePeriod(Table table, string forumName, string threadSubject) { DateTime startDate = DateTime.UtcNow.Subtract(new TimeSpan(21, 0, 0, 0)); DateTime endDate = DateTime.UtcNow.Subtract(new TimeSpan(1, 0, 0, 0)); QueryFilter filter = new QueryFilter("Id", QueryOperator.Equal, forumName + "#" + threadSubject); filter.AddCondition("ReplyDateTime", QueryOperator.Between, startDate, endDate); QueryOperationConfig config = new QueryOperationConfig() { Limit = 2, // 2 items/page. Select = SelectValues.SpecificAttributes, AttributesToGet = new List<string> { "Message", "ReplyDateTime", "PostedBy" }, ConsistentRead = true, Filter = filter }; Search search = table.Query(config); List<Document> documentList = new List<Document>(); do { documentList = search.GetNextSet(); Console.WriteLine("\nFindRepliesPostedWithinTimePeriod: printing replies posted within dates: {0} and {1} ............", startDate, endDate); foreach (var document in documentList) { PrintDocument(document); } } while (!search.IsDone); } private static void FindRepliesInLast15DaysWithConfig(Table table, string forumName, string threadName) { DateTime twoWeeksAgoDate = DateTime.UtcNow - TimeSpan.FromDays(15); QueryFilter filter = new QueryFilter("Id", QueryOperator.Equal, forumName + "#" + threadName); filter.AddCondition("ReplyDateTime", QueryOperator.GreaterThan, twoWeeksAgoDate); // You are specifying optional parameters so use QueryOperationConfig. QueryOperationConfig config = new QueryOperationConfig() { Filter = filter, // Optional parameters. Select = SelectValues.SpecificAttributes, AttributesToGet = new List<string> { "Message", "ReplyDateTime", "PostedBy" }, ConsistentRead = true }; Search search = table.Query(config); List<Document> documentSet = new List<Document>(); do { documentSet = search.GetNextSet(); Console.WriteLine("\nFindRepliesInLast15DaysWithConfig: printing ............"); foreach (var document in documentSet) PrintDocument(document); } while (!search.IsDone); } private static void PrintDocument(Document document) { // count++; Console.WriteLine(); foreach (var attribute in document.GetAttributeNames()) { string stringValue = null; var value = document[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); } } }

Sample Details

Service: dynamodb

Last tested:

Author: AWS

Type: full-example

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