获取有关 DynamoDB 表的信息 - Amazon DynamoDB
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获取有关 DynamoDB 表的信息

以下代码示例显示如何获取有关 DynamoDB 表的信息。

C++
适用于 C++ 的 SDK
提示

要了解如何设置和运行此示例,请参阅 GitHub

Aws::Client::ClientConfiguration clientConfig; if (!region.empty()) clientConfig.region = region; Aws::DynamoDB::DynamoDBClient dynamoClient(clientConfig); Aws::DynamoDB::Model::DescribeTableRequest dtr; dtr.SetTableName(table); const Aws::DynamoDB::Model::DescribeTableOutcome& result = dynamoClient.DescribeTable(dtr); if (result.IsSuccess()) { const Aws::DynamoDB::Model::TableDescription& td = result.GetResult().GetTable(); std::cout << "Table name : " << td.GetTableName() << std::endl; std::cout << "Table ARN : " << td.GetTableArn() << std::endl; std::cout << "Status : " << Aws::DynamoDB::Model::TableStatusMapper::GetNameForTableStatus(td.GetTableStatus()) << std::endl; std::cout << "Item count : " << td.GetItemCount() << std::endl; std::cout << "Size (bytes): " << td.GetTableSizeBytes() << std::endl; const Aws::DynamoDB::Model::ProvisionedThroughputDescription& ptd = td.GetProvisionedThroughput(); std::cout << "Throughput" << std::endl; std::cout << " Read Capacity : " << ptd.GetReadCapacityUnits() << std::endl; std::cout << " Write Capacity: " << ptd.GetWriteCapacityUnits() << std::endl; const Aws::Vector<Aws::DynamoDB::Model::AttributeDefinition>& ad = td.GetAttributeDefinitions(); std::cout << "Attributes" << std::endl; for (const auto& a : ad) std::cout << " " << a.GetAttributeName() << " (" << Aws::DynamoDB::Model::ScalarAttributeTypeMapper::GetNameForScalarAttributeType(a.GetAttributeType()) << ")" << std::endl; } else { std::cout << "Failed to describe table: " << result.GetError().GetMessage(); }
  • 有关 API 详细信息,请参阅《Amazon SDK for C++ API 参考》中的 DescribeTable

Go
SDK for Go V2
提示

要了解如何设置和运行此示例,请参阅 GitHub

// TableBasics encapsulates the Amazon DynamoDB service actions used in the examples. // It contains a DynamoDB service client that is used to act on the specified table. type TableBasics struct { DynamoDbClient *dynamodb.Client TableName string } // TableExists determines whether a DynamoDB table exists. func (basics TableBasics) TableExists() (bool, error) { exists := true _, err := basics.DynamoDbClient.DescribeTable( context.TODO(), &dynamodb.DescribeTableInput{TableName: aws.String(basics.TableName)}, ) if err != nil { var notFoundEx *types.ResourceNotFoundException if errors.As(err, &notFoundEx) { log.Printf("Table %v does not exist.\n", basics.TableName) err = nil } else { log.Printf("Couldn't determine existence of table %v. Here's why: %v\n", basics.TableName, err) } exists = false } return exists, err }
  • 有关 API 详细信息,请参阅《Amazon SDK for Go API 参考》中的 DescribeTable

Java
SDK for Java 2.x
提示

要了解如何设置和运行此示例,请参阅 GitHub

public static void describeDymamoDBTable(DynamoDbClient ddb,String tableName ) { DescribeTableRequest request = DescribeTableRequest.builder() .tableName(tableName) .build(); try { TableDescription tableInfo = ddb.describeTable(request).table(); if (tableInfo != null) { System.out.format("Table name : %s\n", tableInfo.tableName()); System.out.format("Table ARN : %s\n", tableInfo.tableArn()); System.out.format("Status : %s\n", tableInfo.tableStatus()); System.out.format("Item count : %d\n", tableInfo.itemCount().longValue()); System.out.format("Size (bytes): %d\n", tableInfo.tableSizeBytes().longValue()); ProvisionedThroughputDescription throughputInfo = tableInfo.provisionedThroughput(); System.out.println("Throughput"); System.out.format(" Read Capacity : %d\n", throughputInfo.readCapacityUnits().longValue()); System.out.format(" Write Capacity: %d\n", throughputInfo.writeCapacityUnits().longValue()); List<AttributeDefinition> attributes = tableInfo.attributeDefinitions(); System.out.println("Attributes"); for (AttributeDefinition a : attributes) { System.out.format(" %s (%s)\n", a.attributeName(), a.attributeType()); } } } catch (DynamoDbException e) { System.err.println(e.getMessage()); System.exit(1); } System.out.println("\nDone!"); }
  • 有关 API 详细信息,请参阅《Amazon SDK for Java 2.x API 参考》中的 DescribeTable

JavaScript
SDK for JavaScript V3
提示

要了解如何设置和运行此示例,请参阅 GitHub

创建客户端。

// Create service client module using ES6 syntax. import { DynamoDBClient } from "@aws-sdk/client-dynamodb"; // Set the AWS Region. const REGION = "REGION"; //e.g. "us-east-1" // Create an Amazon DynamoDB service client object. const ddbClient = new DynamoDBClient({ region: REGION }); export { ddbClient };

描述表。

// Import required AWS SDK clients and commands for Node.js import { DescribeTableCommand } from "@aws-sdk/client-dynamodb"; import { ddbClient } from "./libs/ddbClient.js"; // Set the parameters export const params = { TableName: "TABLE_NAME" }; //TABLE_NAME export const run = async () => { try { const data = await ddbClient.send(new DescribeTableCommand(params)); console.log("Success", data); // console.log("Success", data.Table.KeySchema); return data; } catch (err) { console.log("Error", err); } }; run();
SDK for JavaScript V2
提示

要了解如何设置和运行此示例,请参阅 GitHub

// Load the AWS SDK for Node.js var AWS = require('aws-sdk'); // Set the region AWS.config.update({region: 'REGION'}); // Create the DynamoDB service object var ddb = new AWS.DynamoDB({apiVersion: '2012-08-10'}); var params = { TableName: process.argv[2] }; // Call DynamoDB to retrieve the selected table descriptions ddb.describeTable(params, function(err, data) { if (err) { console.log("Error", err); } else { console.log("Success", data.Table.KeySchema); } });
Python
适用于 Python (Boto3) 的 SDK
提示

要了解如何设置和运行此示例,请参阅 GitHub

class Movies: """Encapsulates an Amazon DynamoDB table of movie data.""" def __init__(self, dyn_resource): """ :param dyn_resource: A Boto3 DynamoDB resource. """ self.dyn_resource = dyn_resource self.table = None def exists(self, table_name): """ Determines whether a table exists. As a side effect, stores the table in a member variable. :param table_name: The name of the table to check. :return: True when the table exists; otherwise, False. """ try: table = self.dyn_resource.Table(table_name) table.load() exists = True except ClientError as err: if err.response['Error']['Code'] == 'ResourceNotFoundException': exists = False else: logger.error( "Couldn't check for existence of %s. Here's why: %s: %s", table_name, err.response['Error']['Code'], err.response['Error']['Message']) raise else: self.table = table return exists
Ruby
SDK for Ruby
提示

要了解如何设置和运行此示例,请参阅 GitHub

# Determines whether a table exists. As a side effect, stores the table in # a member variable. # # @param table_name [String] The name of the table to check. # @return [Boolean] True when the table exists; otherwise, False. def exists?(table_name) table = Aws::DynamoDB::Table.new(table_name) table.load @table = table rescue Aws::DynamoDB::Errors::ResourceNotFoundException puts("Table #{table_name} doesn't exist. Let's create it.") false rescue Aws::Errors::ServiceError => e puts("Couldn't check for existence of #{table_name}. Here's why:") puts("\t#{e.code}: #{e.message}") raise else !@table.nil? end
  • 有关 API 详细信息,请参阅《Amazon SDK for Ruby API 参考》中的 DescribeTable

有关 Amazon 软件开发工具包开发人员指南和代码示例的完整列表,请参阅 结合使用 DynamoDB 与 Amazon SDK。本主题还包括有关入门的信息以及有关先前的软件开发工具包版本的详细信息。