Read an item from a DynamoDB table - Amazon DynamoDB

Read an item from a DynamoDB table

You can read items from DynamoDB tables using the AWS Management Console, the AWS CLI, or an AWS SDK. For more information on items, see Core components of Amazon DynamoDB.

Read an item from a DynamoDB table using an AWS SDK

The following code examples show how to read an item from a DynamoDB table using an AWS SDK.

C++
SDK for C++
Tip

To learn how to set up and run this example, see GitHub.

Aws::Client::ClientConfiguration clientConfig; Aws::DynamoDB::DynamoDBClient dynamoClient(clientConfig); Aws::DynamoDB::Model::GetItemRequest req; // Set up the request. req.SetTableName(table); Aws::DynamoDB::Model::AttributeValue hashKey; hashKey.SetS(keyval); req.AddKey(key, hashKey); // Retrieve the item's fields and values const Aws::DynamoDB::Model::GetItemOutcome& result = dynamoClient.GetItem(req); if (result.IsSuccess()) { // Reference the retrieved fields/values. const Aws::Map<Aws::String, Aws::DynamoDB::Model::AttributeValue>& item = result.GetResult().GetItem(); if (item.size() > 0) { // Output each retrieved field and its value. for (const auto& i : item) std::cout << "Values: " << i.first << ": " << i.second.GetS() << std::endl; } else { std::cout << "No item found with the key " << key << std::endl; } } else { std::cout << "Failed to get item: " << result.GetError().GetMessage(); }
  • For API details, see GetItem in AWS SDK for C++ API Reference.

Go
SDK for Go V2
Tip

To learn how to set up and run this example, see 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 } // GetMovie gets movie data from the DynamoDB table by using the primary composite key // made of title and year. func (basics TableBasics) GetMovie(title string, year int) (Movie, error) { movie := Movie{Title: title, Year: year} response, err := basics.DynamoDbClient.GetItem(context.TODO(), &dynamodb.GetItemInput{ Key: movie.GetKey(), TableName: aws.String(basics.TableName), }) if err != nil { log.Printf("Couldn't get info about %v. Here's why: %v\n", title, err) } else { err = attributevalue.UnmarshalMap(response.Item, &movie) if err != nil { log.Printf("Couldn't unmarshal response. Here's why: %v\n", err) } } return movie, err }
  • For API details, see GetItem in AWS SDK for Go API Reference.

Java
SDK for Java 2.x
Tip

To learn how to set up and run this example, see GitHub.

Gets an item from a table by using the DynamoDbClient.

public static int queryTable(DynamoDbClient ddb, String tableName, String partitionKeyName, String partitionKeyVal, String partitionAlias) { // Set up an alias for the partition key name in case it's a reserved word. HashMap<String,String> attrNameAlias = new HashMap<String,String>(); attrNameAlias.put(partitionAlias, partitionKeyName); // Set up mapping of the partition name with the value. HashMap<String, AttributeValue> attrValues = new HashMap<>(); attrValues.put(":"+partitionKeyName, AttributeValue.builder() .s(partitionKeyVal) .build()); QueryRequest queryReq = QueryRequest.builder() .tableName(tableName) .keyConditionExpression(partitionAlias + " = :" + partitionKeyName) .expressionAttributeNames(attrNameAlias) .expressionAttributeValues(attrValues) .build(); try { QueryResponse response = ddb.query(queryReq); return response.count(); } catch (DynamoDbException e) { System.err.println(e.getMessage()); System.exit(1); } return -1; }
  • For API details, see GetItem in AWS SDK for Java 2.x API Reference.

JavaScript
SDK for JavaScript V3
Tip

To learn how to set up and run this example, see GitHub.

Create the client.

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

Create the DynamoDB document client.

// Create a service client module using ES6 syntax. import { DynamoDBDocumentClient } from "@aws-sdk/lib-dynamodb"; import { ddbClient } from "./ddbClient.js"; // Set the AWS Region. const REGION = "REGION"; // For example, "us-east-1". const marshallOptions = { // Whether to automatically convert empty strings, blobs, and sets to `null`. convertEmptyValues: false, // false, by default. // Whether to remove undefined values while marshalling. removeUndefinedValues: false, // false, by default. // Whether to convert typeof object to map attribute. convertClassInstanceToMap: false, // false, by default. }; const unmarshallOptions = { // Whether to return numbers as a string instead of converting them to native JavaScript numbers. wrapNumbers: false, // false, by default. }; const translateConfig = { marshallOptions, unmarshallOptions }; // Create the DynamoDB document client. const ddbDocClient = DynamoDBDocumentClient.from(ddbClient, translateConfig); export { ddbDocClient };

Get an item from a table.

import { GetCommand } from "@aws-sdk/lib-dynamodb"; import { ddbDocClient } from "../libs/ddbDocClient.js"; // Set the parameters. export const params = { TableName: "TABLE_NAME", Key: { primaryKey: "VALUE_1", sortKey: "VALUE_2", }, }; export const getItem = async () => { try { const data = await ddbDocClient.send(new GetCommand(params)); console.log("Success :", data.Item); } catch (err) { console.log("Error", err); } }; getItem();

Get an item from a table using PartiQL.

// Import required AWS SDK clients and commands for Node.js. import { ExecuteStatementCommand } from "@aws-sdk/client-dynamodb"; import { ddbDocClient } from "../libs/ddbDocClient"; const tableName = process.argv[2]; const movieTitle1 = process.argv[3]; export const run = async (tableName, movieTitle1) => { const params = { Statement: "SELECT * FROM " + tableName + " where title=?", Parameters: [{ S: movieTitle1 }], }; try { const data = await ddbDocClient.send(new ExecuteStatementCommand(params)); for (let i = 0; i < data.Items.length; i++) { console.log( "Success. The query return the following data. Item " + i, data.Items[i].year, data.Items[i].title, data.Items[i].info ); } return "Run successfully"; // For unit tests. } catch (err) { console.error(err); } }; run(tableName, movieTitle1);

Get items by batch from a table using PartiQL.

// Import required AWS SDK clients and commands for Node.js. import { BatchExecuteStatementCommand } from "@aws-sdk/client-dynamodb"; import { ddbDocClient } from "../libs/ddbDocClient.js"; const tableName = process.argv[2]; const movieYear1 = process.argv[3]; const movieTitle1 = process.argv[4]; const movieYear2 = process.argv[5]; const movieTitle2 = process.argv[6]; export const run = async ( tableName, movieYear1, movieTitle1, movieYear2, movieTitle2 ) => { const params = { Statements: [ { Statement: "SELECT * FROM " + tableName + " where title=? and year=?", Parameters: [{ S: movieTitle1 }, { N: movieYear1 }], }, { Statement: "SELECT * FROM " + tableName + " where title=? and year=?", Parameters: [{ S: movieTitle2 }, { N: movieYear2 }], }, ], }; try { const data = await ddbDocClient.send( new BatchExecuteStatementCommand(params) ); for (let i = 0; i < data.Responses.length; i++) { console.log(data.Responses[i].Item.year); console.log(data.Responses[i].Item.title); } return "Run successfully"; // For unit tests. } catch (err) { console.error(err); } }; run(tableName, movieYear1, movieTitle1, movieYear2, movieTitle2);
  • For API details, see GetItem in AWS SDK for JavaScript API Reference.

SDK for JavaScript V2
Tip

To learn how to set up and run this example, see GitHub.

Get an item from a table.

// 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: 'TABLE', Key: { 'KEY_NAME': {N: '001'} }, ProjectionExpression: 'ATTRIBUTE_NAME' }; // Call DynamoDB to read the item from the table ddb.getItem(params, function(err, data) { if (err) { console.log("Error", err); } else { console.log("Success", data.Item); } });

Get an item from a table using the DynamoDB document client.

// Load the AWS SDK for Node.js var AWS = require('aws-sdk'); // Set the region AWS.config.update({region: 'REGION'}); // Create DynamoDB document client var docClient = new AWS.DynamoDB.DocumentClient({apiVersion: '2012-08-10'}); var params = { TableName: 'EPISODES_TABLE', Key: {'KEY_NAME': VALUE} }; docClient.get(params, function(err, data) { if (err) { console.log("Error", err); } else { console.log("Success", data.Item); } });
Kotlin
SDK for Kotlin
Note

This is prerelease documentation for a feature in preview release. It is subject to change.

Tip

To learn how to set up and run this example, see GitHub.

suspend fun getSpecificItem(tableNameVal: String, keyName: String, keyVal: String) { val keyToGet = mutableMapOf<String, AttributeValue>() keyToGet[keyName] = AttributeValue.S(keyVal) val request = GetItemRequest { key = keyToGet tableName = tableNameVal } DynamoDbClient { region = "us-east-1" }.use { ddb -> val returnedItem = ddb.getItem(request) val numbersMap = returnedItem.item numbersMap?.forEach { key1 -> println(key1.key) println(key1.value) } } }
  • For API details, see GetItem in AWS SDK for Kotlin API reference.

PHP
SDK for PHP
Tip

To learn how to set up and run this example, see GitHub.

$movie = $service->getItemByKey($tableName, $key); echo "\nThe movie {$movie['Item']['title']['S']} was released in {$movie['Item']['year']['N']}.\n"; public function getItemByKey(string $tableName, array $key) { return $this->dynamoDbClient->getItem([ 'Key' => $key['Item'], 'TableName' => $tableName, ]); }
  • For API details, see GetItem in AWS SDK for PHP API Reference.

Python
SDK for Python (Boto3)
Tip

To learn how to set up and run this example, see 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 get_movie(self, title, year): """ Gets movie data from the table for a specific movie. :param title: The title of the movie. :param year: The release year of the movie. :return: The data about the requested movie. """ try: response = self.table.get_item(Key={'year': year, 'title': title}) except ClientError as err: logger.error( "Couldn't get movie %s from table %s. Here's why: %s: %s", title, self.table.name, err.response['Error']['Code'], err.response['Error']['Message']) raise else: return response['Item']
  • For API details, see GetItem in AWS SDK for Python (Boto3) API Reference.

Ruby
SDK for Ruby
Tip

To learn how to set up and run this example, see GitHub.

# Gets movie data from the table for a specific movie. # # @param title [String] The title of the movie. # @param year [Integer] The release year of the movie. # @return [Hash] The data about the requested movie. def get_movie(title, year) response = @table.get_item(key: {"year" => year, "title" => title}) rescue Aws::Errors::ServiceError => e puts("Couldn't get movie #{title} from table #{@table.name}. Here's why:") puts("\t#{e.code}: #{e.message}") raise else response.item end
  • For API details, see GetItem in AWS SDK for Ruby API Reference.

For more DynamoDB examples, see Code examples for DynamoDB using AWS SDKs.