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Amazon DynamoDB
開発者ガイド (API バージョン 2012-08-10)

例: AWS SDK for .NET 低レベル API を使用した グローバルセカンダリインデックス

次の C# コード例では、グローバルセカンダリインデックス の操作方法を示します。この例では、Issues という名前のテーブルを作成します。このテーブルは、ソフトウェア開発の単純なバグ追跡システムで使用される可能性があります。パーティションキーは IssueId で、ソートキーは Title です。このテーブルには 3 つの グローバルセカンダリインデックス があります。

  • CreateDateIndex – パーティションキーは CreateDate で、ソートキーは IssueId です。テーブルキーに加えて、属性 Description と Status がインデックスに射影されます。

  • TitleIndex – パーティションキーは Title で、ソートキーは IssueId です。テーブルキー以外の属性は、インデックスに射影されません。

  • DueDateIndex – パーティションキーは DueDate で、ソートキーはありません。すべてのテーブル属性がインデックスに射影されます。

Issues テーブルを作成した後、プログラムによって、ソフトウェアバグレポートを表すデータがテーブルにロードされ、グローバルセカンダリインデックス を使用してそのデータに対してクエリが実行されます。最後に、プログラムによって Issues テーブルが削除されます。

次のサンプルをテストするための詳しい手順については、「.NET コードサンプル」を参照してください。

using System; using System.Collections.Generic; using System.Linq; using Amazon.DynamoDBv2; using Amazon.DynamoDBv2.DataModel; using Amazon.DynamoDBv2.DocumentModel; using Amazon.DynamoDBv2.Model; using Amazon.Runtime; using Amazon.SecurityToken; namespace com.amazonaws.codesamples { class LowLevelGlobalSecondaryIndexExample { private static AmazonDynamoDBClient client = new AmazonDynamoDBClient(); public static String tableName = "Issues"; public static void Main(string[] args) { CreateTable(); LoadData(); QueryIndex("CreateDateIndex"); QueryIndex("TitleIndex"); QueryIndex("DueDateIndex"); DeleteTable(tableName); Console.WriteLine("To continue, press enter"); Console.Read(); } private static void CreateTable() { // Attribute definitions var attributeDefinitions = new List<AttributeDefinition>() { {new AttributeDefinition { AttributeName = "IssueId", AttributeType = "S" }}, {new AttributeDefinition { AttributeName = "Title", AttributeType = "S" }}, {new AttributeDefinition { AttributeName = "CreateDate", AttributeType = "S" }}, {new AttributeDefinition { AttributeName = "DueDate", AttributeType = "S" }} }; // Key schema for table var tableKeySchema = new List<KeySchemaElement>() { { new KeySchemaElement { AttributeName= "IssueId", KeyType = "HASH" //Partition key } }, { new KeySchemaElement { AttributeName = "Title", KeyType = "RANGE" //Sort key } } }; // Initial provisioned throughput settings for the indexes var ptIndex = new ProvisionedThroughput { ReadCapacityUnits = 1L, WriteCapacityUnits = 1L }; // CreateDateIndex var createDateIndex = new GlobalSecondaryIndex() { IndexName = "CreateDateIndex", ProvisionedThroughput = ptIndex, KeySchema = { new KeySchemaElement { AttributeName = "CreateDate", KeyType = "HASH" //Partition key }, new KeySchemaElement { AttributeName = "IssueId", KeyType = "RANGE" //Sort key } }, Projection = new Projection { ProjectionType = "INCLUDE", NonKeyAttributes = { "Description", "Status" } } }; // TitleIndex var titleIndex = new GlobalSecondaryIndex() { IndexName = "TitleIndex", ProvisionedThroughput = ptIndex, KeySchema = { new KeySchemaElement { AttributeName = "Title", KeyType = "HASH" //Partition key }, new KeySchemaElement { AttributeName = "IssueId", KeyType = "RANGE" //Sort key } }, Projection = new Projection { ProjectionType = "KEYS_ONLY" } }; // DueDateIndex var dueDateIndex = new GlobalSecondaryIndex() { IndexName = "DueDateIndex", ProvisionedThroughput = ptIndex, KeySchema = { new KeySchemaElement { AttributeName = "DueDate", KeyType = "HASH" //Partition key } }, Projection = new Projection { ProjectionType = "ALL" } }; var createTableRequest = new CreateTableRequest { TableName = tableName, ProvisionedThroughput = new ProvisionedThroughput { ReadCapacityUnits = (long)1, WriteCapacityUnits = (long)1 }, AttributeDefinitions = attributeDefinitions, KeySchema = tableKeySchema, GlobalSecondaryIndexes = { createDateIndex, titleIndex, dueDateIndex } }; Console.WriteLine("Creating table " + tableName + "..."); client.CreateTable(createTableRequest); WaitUntilTableReady(tableName); } private static void LoadData() { Console.WriteLine("Loading data into table " + tableName + "..."); // IssueId, Title, // Description, // CreateDate, LastUpdateDate, DueDate, // Priority, Status putItem("A-101", "Compilation error", "Can't compile Project X - bad version number. What does this mean?", "2013-11-01", "2013-11-02", "2013-11-10", 1, "Assigned"); putItem("A-102", "Can't read data file", "The main data file is missing, or the permissions are incorrect", "2013-11-01", "2013-11-04", "2013-11-30", 2, "In progress"); putItem("A-103", "Test failure", "Functional test of Project X produces errors", "2013-11-01", "2013-11-02", "2013-11-10", 1, "In progress"); putItem("A-104", "Compilation error", "Variable 'messageCount' was not initialized.", "2013-11-15", "2013-11-16", "2013-11-30", 3, "Assigned"); putItem("A-105", "Network issue", "Can't ping IP address 127.0.0.1. Please fix this.", "2013-11-15", "2013-11-16", "2013-11-19", 5, "Assigned"); } private static void putItem( String issueId, String title, String description, String createDate, String lastUpdateDate, String dueDate, Int32 priority, String status) { Dictionary<String, AttributeValue> item = new Dictionary<string, AttributeValue>(); item.Add("IssueId", new AttributeValue { S = issueId }); item.Add("Title", new AttributeValue { S = title }); item.Add("Description", new AttributeValue { S = description }); item.Add("CreateDate", new AttributeValue { S = createDate }); item.Add("LastUpdateDate", new AttributeValue { S = lastUpdateDate }); item.Add("DueDate", new AttributeValue { S = dueDate }); item.Add("Priority", new AttributeValue { N = priority.ToString() }); item.Add("Status", new AttributeValue { S = status }); try { client.PutItem(new PutItemRequest { TableName = tableName, Item = item }); } catch (Exception e) { Console.WriteLine(e.ToString()); } } private static void QueryIndex(string indexName) { Console.WriteLine ("\n***********************************************************\n"); Console.WriteLine("Querying index " + indexName + "..."); QueryRequest queryRequest = new QueryRequest { TableName = tableName, IndexName = indexName, ScanIndexForward = true }; String keyConditionExpression; Dictionary<string, AttributeValue> expressionAttributeValues = new Dictionary<string, AttributeValue>(); if (indexName == "CreateDateIndex") { Console.WriteLine("Issues filed on 2013-11-01\n"); keyConditionExpression = "CreateDate = :v_date and begins_with(IssueId, :v_issue)"; expressionAttributeValues.Add(":v_date", new AttributeValue { S = "2013-11-01" }); expressionAttributeValues.Add(":v_issue", new AttributeValue { S = "A-" }); } else if (indexName == "TitleIndex") { Console.WriteLine("Compilation errors\n"); keyConditionExpression = "Title = :v_title and begins_with(IssueId, :v_issue)"; expressionAttributeValues.Add(":v_title", new AttributeValue { S = "Compilation error" }); expressionAttributeValues.Add(":v_issue", new AttributeValue { S = "A-" }); // Select queryRequest.Select = "ALL_PROJECTED_ATTRIBUTES"; } else if (indexName == "DueDateIndex") { Console.WriteLine("Items that are due on 2013-11-30\n"); keyConditionExpression = "DueDate = :v_date"; expressionAttributeValues.Add(":v_date", new AttributeValue { S = "2013-11-30" }); // Select queryRequest.Select = "ALL_PROJECTED_ATTRIBUTES"; } else { Console.WriteLine("\nNo valid index name provided"); return; } queryRequest.KeyConditionExpression = keyConditionExpression; queryRequest.ExpressionAttributeValues = expressionAttributeValues; var result = client.Query(queryRequest); var items = result.Items; foreach (var currentItem in items) { foreach (string attr in currentItem.Keys) { if (attr == "Priority") { Console.WriteLine(attr + "---> " + currentItem[attr].N); } else { Console.WriteLine(attr + "---> " + currentItem[attr].S); } } Console.WriteLine(); } } private static void DeleteTable(string tableName) { Console.WriteLine("Deleting table " + tableName + "..."); client.DeleteTable(new DeleteTableRequest { TableName = tableName }); WaitForTableToBeDeleted(tableName); } private static void WaitUntilTableReady(string tableName) { string status = null; // Let us wait until table is created. Call DescribeTable. do { System.Threading.Thread.Sleep(5000); // Wait 5 seconds. try { var res = client.DescribeTable(new DescribeTableRequest { TableName = tableName }); Console.WriteLine("Table name: {0}, status: {1}", res.Table.TableName, res.Table.TableStatus); status = res.Table.TableStatus; } catch (ResourceNotFoundException) { // DescribeTable is eventually consistent. So you might // get resource not found. So we handle the potential exception. } } while (status != "ACTIVE"); } private static void WaitForTableToBeDeleted(string tableName) { bool tablePresent = true; while (tablePresent) { System.Threading.Thread.Sleep(5000); // Wait 5 seconds. try { var res = client.DescribeTable(new DescribeTableRequest { TableName = tableName }); Console.WriteLine("Table name: {0}, status: {1}", res.Table.TableName, res.Table.TableStatus); } catch (ResourceNotFoundException) { tablePresent = false; } } } } }