Gunakan GetItem dengan AWS SDK atau CLI - Amazon DynamoDB

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Gunakan GetItem dengan AWS SDK atau CLI

Contoh kode berikut menunjukkan cara menggunakanGetItem.

Contoh tindakan adalah kutipan kode dari program yang lebih besar dan harus dijalankan dalam konteks. Anda dapat melihat tindakan ini dalam konteks dalam contoh kode berikut:

.NET
AWS SDK for .NET
catatan

Ada lebih banyak tentang GitHub. Temukan contoh lengkapnya dan pelajari cara pengaturan dan menjalankannya di Repositori Contoh Kode AWS.

/// <summary> /// Gets information about an existing movie from the table. /// </summary> /// <param name="client">An initialized Amazon DynamoDB client object.</param> /// <param name="newMovie">A Movie object containing information about /// the movie to retrieve.</param> /// <param name="tableName">The name of the table containing the movie.</param> /// <returns>A Dictionary object containing information about the item /// retrieved.</returns> public static async Task<Dictionary<string, AttributeValue>> GetItemAsync(AmazonDynamoDBClient client, Movie newMovie, string tableName) { var key = new Dictionary<string, AttributeValue> { ["title"] = new AttributeValue { S = newMovie.Title }, ["year"] = new AttributeValue { N = newMovie.Year.ToString() }, }; var request = new GetItemRequest { Key = key, TableName = tableName, }; var response = await client.GetItemAsync(request); return response.Item; }
  • Untuk API detailnya, lihat GetItemdi AWS SDK for .NET APIReferensi.

Bash
AWS CLI dengan skrip Bash
catatan

Ada lebih banyak tentang GitHub. Temukan contoh lengkapnya dan pelajari cara pengaturan dan menjalankannya di Repositori Contoh Kode AWS.

############################################################################# # function dynamodb_get_item # # This function gets an item from a DynamoDB table. # # Parameters: # -n table_name -- The name of the table. # -k keys -- Path to json file containing the keys that identify the item to get. # [-q query] -- Optional JMESPath query expression. # # Returns: # The item as text output. # And: # 0 - If successful. # 1 - If it fails. ############################################################################ function dynamodb_get_item() { local table_name keys query response local option OPTARG # Required to use getopts command in a function. # ###################################### # Function usage explanation ####################################### function usage() { echo "function dynamodb_get_item" echo "Get an item from a DynamoDB table." echo " -n table_name -- The name of the table." echo " -k keys -- Path to json file containing the keys that identify the item to get." echo " [-q query] -- Optional JMESPath query expression." echo "" } query="" while getopts "n:k:q:h" option; do case "${option}" in n) table_name="${OPTARG}" ;; k) keys="${OPTARG}" ;; q) query="${OPTARG}" ;; h) usage return 0 ;; \?) echo "Invalid parameter" usage return 1 ;; esac done export OPTIND=1 if [[ -z "$table_name" ]]; then errecho "ERROR: You must provide a table name with the -n parameter." usage return 1 fi if [[ -z "$keys" ]]; then errecho "ERROR: You must provide a keys json file path the -k parameter." usage return 1 fi if [[ -n "$query" ]]; then response=$(aws dynamodb get-item \ --table-name "$table_name" \ --key file://"$keys" \ --output text \ --query "$query") else response=$( aws dynamodb get-item \ --table-name "$table_name" \ --key file://"$keys" \ --output text ) fi local error_code=${?} if [[ $error_code -ne 0 ]]; then aws_cli_error_log $error_code errecho "ERROR: AWS reports get-item operation failed.$response" return 1 fi if [[ -n "$query" ]]; then echo "$response" | sed "/^\t/s/\t//1" # Remove initial tab that the JMSEPath query inserts on some strings. else echo "$response" fi return 0 }

Fungsi utilitas yang digunakan dalam contoh ini.

############################################################################### # function errecho # # This function outputs everything sent to it to STDERR (standard error output). ############################################################################### function errecho() { printf "%s\n" "$*" 1>&2 } ############################################################################## # function aws_cli_error_log() # # This function is used to log the error messages from the AWS CLI. # # See https://docs.aws.amazon.com/cli/latest/topic/return-codes.html#cli-aws-help-return-codes. # # The function expects the following argument: # $1 - The error code returned by the AWS CLI. # # Returns: # 0: - Success. # ############################################################################## function aws_cli_error_log() { local err_code=$1 errecho "Error code : $err_code" if [ "$err_code" == 1 ]; then errecho " One or more S3 transfers failed." elif [ "$err_code" == 2 ]; then errecho " Command line failed to parse." elif [ "$err_code" == 130 ]; then errecho " Process received SIGINT." elif [ "$err_code" == 252 ]; then errecho " Command syntax invalid." elif [ "$err_code" == 253 ]; then errecho " The system environment or configuration was invalid." elif [ "$err_code" == 254 ]; then errecho " The service returned an error." elif [ "$err_code" == 255 ]; then errecho " 255 is a catch-all error." fi return 0 }
  • Untuk API detailnya, lihat GetItemdi Referensi AWS CLI Perintah.

C++
SDKuntuk C ++
catatan

Ada lebih banyak tentang GitHub. Temukan contoh lengkapnya dan pelajari cara pengaturan dan menjalankannya di Repositori Contoh Kode AWS.

//! Get an item from an Amazon DynamoDB table. /*! \sa getItem() \param tableName: The table name. \param partitionKey: The partition key. \param partitionValue: The value for the partition key. \param clientConfiguration: AWS client configuration. \return bool: Function succeeded. */ bool AwsDoc::DynamoDB::getItem(const Aws::String &tableName, const Aws::String &partitionKey, const Aws::String &partitionValue, const Aws::Client::ClientConfiguration &clientConfiguration) { Aws::DynamoDB::DynamoDBClient dynamoClient(clientConfiguration); Aws::DynamoDB::Model::GetItemRequest request; // Set up the request. request.SetTableName(tableName); request.AddKey(partitionKey, Aws::DynamoDB::Model::AttributeValue().SetS(partitionValue)); // Retrieve the item's fields and values. const Aws::DynamoDB::Model::GetItemOutcome &outcome = dynamoClient.GetItem(request); if (outcome.IsSuccess()) { // Reference the retrieved fields/values. const Aws::Map<Aws::String, Aws::DynamoDB::Model::AttributeValue> &item = outcome.GetResult().GetItem(); if (!item.empty()) { // 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 " << partitionKey << std::endl; } } else { std::cerr << "Failed to get item: " << outcome.GetError().GetMessage(); } return outcome.IsSuccess(); }
  • Untuk API detailnya, lihat GetItemdi AWS SDK for C++ APIReferensi.

CLI
AWS CLI

Contoh 1: Untuk membaca item dalam tabel

get-itemContoh berikut mengambil item dari MusicCollection tabel. Tabel memiliki kunci hash-and-range utama (ArtistdanSongTitle), jadi Anda harus menentukan kedua atribut ini. Perintah tersebut juga meminta informasi tentang kapasitas baca yang dikonsumsi oleh operasi.

aws dynamodb get-item \ --table-name MusicCollection \ --key file://key.json \ --return-consumed-capacity TOTAL

Isi dari key.json:

{ "Artist": {"S": "Acme Band"}, "SongTitle": {"S": "Happy Day"} }

Output:

{ "Item": { "AlbumTitle": { "S": "Songs About Life" }, "SongTitle": { "S": "Happy Day" }, "Artist": { "S": "Acme Band" } }, "ConsumedCapacity": { "TableName": "MusicCollection", "CapacityUnits": 0.5 } }

Untuk informasi selengkapnya, lihat Membaca Item di Panduan Pengembang Amazon DynamoDB.

Contoh 2: Untuk membaca item menggunakan pembacaan yang konsisten

Contoh berikut mengambil item dari MusicCollection tabel menggunakan pembacaan yang sangat konsisten.

aws dynamodb get-item \ --table-name MusicCollection \ --key file://key.json \ --consistent-read \ --return-consumed-capacity TOTAL

Isi dari key.json:

{ "Artist": {"S": "Acme Band"}, "SongTitle": {"S": "Happy Day"} }

Output:

{ "Item": { "AlbumTitle": { "S": "Songs About Life" }, "SongTitle": { "S": "Happy Day" }, "Artist": { "S": "Acme Band" } }, "ConsumedCapacity": { "TableName": "MusicCollection", "CapacityUnits": 1.0 } }

Untuk informasi selengkapnya, lihat Membaca Item di Panduan Pengembang Amazon DynamoDB.

Contoh 3: Untuk mengambil atribut tertentu dari suatu item

Contoh berikut menggunakan ekspresi proyeksi untuk mengambil hanya tiga atribut dari item yang diinginkan.

aws dynamodb get-item \ --table-name ProductCatalog \ --key '{"Id": {"N": "102"}}' \ --projection-expression "#T, #C, #P" \ --expression-attribute-names file://names.json

Isi dari names.json:

{ "#T": "Title", "#C": "ProductCategory", "#P": "Price" }

Output:

{ "Item": { "Price": { "N": "20" }, "Title": { "S": "Book 102 Title" }, "ProductCategory": { "S": "Book" } } }

Untuk informasi selengkapnya, lihat Membaca Item di Panduan Pengembang Amazon DynamoDB.

  • Untuk API detailnya, lihat GetItemdi Referensi AWS CLI Perintah.

Go
SDKuntuk Go V2
catatan

Ada lebih banyak tentang GitHub. Temukan contoh lengkapnya dan pelajari cara pengaturan dan menjalankannya di Repositori Contoh Kode AWS.

// 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(ctx context.Context, title string, year int) (Movie, error) { movie := Movie{Title: title, Year: year} response, err := basics.DynamoDbClient.GetItem(ctx, &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 } // Movie encapsulates data about a movie. Title and Year are the composite primary key // of the movie in Amazon DynamoDB. Title is the sort key, Year is the partition key, // and Info is additional data. type Movie struct { Title string `dynamodbav:"title"` Year int `dynamodbav:"year"` Info map[string]interface{} `dynamodbav:"info"` } // GetKey returns the composite primary key of the movie in a format that can be // sent to DynamoDB. func (movie Movie) GetKey() map[string]types.AttributeValue { title, err := attributevalue.Marshal(movie.Title) if err != nil { panic(err) } year, err := attributevalue.Marshal(movie.Year) if err != nil { panic(err) } return map[string]types.AttributeValue{"title": title, "year": year} } // String returns the title, year, rating, and plot of a movie, formatted for the example. func (movie Movie) String() string { return fmt.Sprintf("%v\n\tReleased: %v\n\tRating: %v\n\tPlot: %v\n", movie.Title, movie.Year, movie.Info["rating"], movie.Info["plot"]) }
  • Untuk API detailnya, lihat GetItemdi AWS SDK for Go APIReferensi.

Java
SDKuntuk Java 2.x
catatan

Ada lebih banyak tentang GitHub. Temukan contoh lengkapnya dan pelajari cara pengaturan dan menjalankannya di Repositori Contoh Kode AWS.

Mendapat item dari tabel dengan menggunakan DynamoDbClient.

import software.amazon.awssdk.regions.Region; import software.amazon.awssdk.services.dynamodb.model.DynamoDbException; import software.amazon.awssdk.services.dynamodb.DynamoDbClient; import software.amazon.awssdk.services.dynamodb.model.AttributeValue; import software.amazon.awssdk.services.dynamodb.model.GetItemRequest; import java.util.HashMap; import java.util.Map; import java.util.Set; /** * Before running this Java V2 code example, set up your development * environment, including your credentials. * * For more information, see the following documentation topic: * * https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html * * To get an item from an Amazon DynamoDB table using the AWS SDK for Java V2, * its better practice to use the * Enhanced Client, see the EnhancedGetItem example. */ public class GetItem { public static void main(String[] args) { final String usage = """ Usage: <tableName> <key> <keyVal> Where: tableName - The Amazon DynamoDB table from which an item is retrieved (for example, Music3).\s key - The key used in the Amazon DynamoDB table (for example, Artist).\s keyval - The key value that represents the item to get (for example, Famous Band). """; if (args.length != 3) { System.out.println(usage); System.exit(1); } String tableName = args[0]; String key = args[1]; String keyVal = args[2]; System.out.format("Retrieving item \"%s\" from \"%s\"\n", keyVal, tableName); Region region = Region.US_EAST_1; DynamoDbClient ddb = DynamoDbClient.builder() .region(region) .build(); getDynamoDBItem(ddb, tableName, key, keyVal); ddb.close(); } public static void getDynamoDBItem(DynamoDbClient ddb, String tableName, String key, String keyVal) { HashMap<String, AttributeValue> keyToGet = new HashMap<>(); keyToGet.put(key, AttributeValue.builder() .s(keyVal) .build()); GetItemRequest request = GetItemRequest.builder() .key(keyToGet) .tableName(tableName) .build(); try { // If there is no matching item, GetItem does not return any data. Map<String, AttributeValue> returnedItem = ddb.getItem(request).item(); if (returnedItem.isEmpty()) System.out.format("No item found with the key %s!\n", key); else { Set<String> keys = returnedItem.keySet(); System.out.println("Amazon DynamoDB table attributes: \n"); for (String key1 : keys) { System.out.format("%s: %s\n", key1, returnedItem.get(key1).toString()); } } } catch (DynamoDbException e) { System.err.println(e.getMessage()); System.exit(1); } } }
  • Untuk API detailnya, lihat GetItemdi AWS SDK for Java 2.x APIReferensi.

JavaScript
SDKuntuk JavaScript (v3)
catatan

Ada lebih banyak tentang GitHub. Temukan contoh lengkapnya dan pelajari cara pengaturan dan menjalankannya di Repositori Contoh Kode AWS.

Contoh ini menggunakan klien dokumen untuk menyederhanakan penggunaan item di DynamoDB. Untuk API detailnya lihat GetCommand.

import { DynamoDBClient } from "@aws-sdk/client-dynamodb"; import { DynamoDBDocumentClient, GetCommand } from "@aws-sdk/lib-dynamodb"; const client = new DynamoDBClient({}); const docClient = DynamoDBDocumentClient.from(client); export const main = async () => { const command = new GetCommand({ TableName: "AngryAnimals", Key: { CommonName: "Shoebill", }, }); const response = await docClient.send(command); console.log(response); return response; };
  • Untuk API detailnya, lihat GetItemdi AWS SDK for JavaScript APIReferensi.

SDKuntuk JavaScript (v2)
catatan

Ada lebih banyak tentang GitHub. Temukan contoh lengkapnya dan pelajari cara pengaturan dan menjalankannya di Repositori Contoh Kode AWS.

Dapatkan item dari tabel.

// 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); } });

Dapatkan item dari tabel menggunakan klien dokumen DynamoDB.

// 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
SDKuntuk Kotlin
catatan

Ada lebih banyak tentang GitHub. Temukan contoh lengkapnya dan pelajari cara pengaturan dan menjalankannya di Repositori Contoh Kode AWS.

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) } } }
  • Untuk API detailnya, lihat GetItem AWSSDKAPIreferensi Kotlin.

PHP
SDKuntuk PHP
catatan

Ada lebih banyak tentang GitHub. Temukan contoh lengkapnya dan pelajari cara pengaturan dan menjalankannya di Repositori Contoh Kode AWS.

$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, ]); }
  • Untuk API detailnya, lihat GetItemdi AWS SDK for PHP APIReferensi.

PowerShell
Alat untuk PowerShell

Contoh 1: Mengembalikan item DynamoDB dengan SongTitle kunci partisi dan kunci sort Artist.

$key = @{ SongTitle = 'Somewhere Down The Road' Artist = 'No One You Know' } | ConvertTo-DDBItem Get-DDBItem -TableName 'Music' -Key $key | ConvertFrom-DDBItem

Output:

Name Value ---- ----- Genre Country SongTitle Somewhere Down The Road Price 1.94 Artist No One You Know CriticRating 9 AlbumTitle Somewhat Famous
  • Untuk API detailnya, lihat GetItemdi AWS Tools for PowerShell Referensi Cmdlet.

Python
SDKuntuk Python (Boto3)
catatan

Ada lebih banyak tentang GitHub. Temukan contoh lengkapnya dan pelajari cara pengaturan dan menjalankannya di Repositori Contoh Kode AWS.

class Movies: """Encapsulates an Amazon DynamoDB table of movie data. Example data structure for a movie record in this table: { "year": 1999, "title": "For Love of the Game", "info": { "directors": ["Sam Raimi"], "release_date": "1999-09-15T00:00:00Z", "rating": 6.3, "plot": "A washed up pitcher flashes through his career.", "rank": 4987, "running_time_secs": 8220, "actors": [ "Kevin Costner", "Kelly Preston", "John C. Reilly" ] } } """ def __init__(self, dyn_resource): """ :param dyn_resource: A Boto3 DynamoDB resource. """ self.dyn_resource = dyn_resource # The table variable is set during the scenario in the call to # 'exists' if the table exists. Otherwise, it is set by 'create_table'. 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"]
  • Untuk API detailnya, lihat GetItem AWSSDKReferensi Python (Boto3). API

Ruby
SDKuntuk Ruby
catatan

Ada lebih banyak tentang GitHub. Temukan contoh lengkapnya dan pelajari cara pengaturan dan menjalankannya di Repositori Contoh Kode AWS.

class DynamoDBBasics attr_reader :dynamo_resource, :table def initialize(table_name) client = Aws::DynamoDB::Client.new(region: 'us-east-1') @dynamo_resource = Aws::DynamoDB::Resource.new(client: client) @table = @dynamo_resource.table(table_name) end # 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_item(title, year) @table.get_item(key: { 'year' => year, 'title' => title }) rescue Aws::DynamoDB::Errors::ServiceError => e puts("Couldn't get movie #{title} (#{year}) from table #{@table.name}:\n") puts("\t#{e.code}: #{e.message}") raise end
  • Untuk API detailnya, lihat GetItemdi AWS SDK for Ruby APIReferensi.

SAP ABAP
SDKuntuk SAP ABAP
catatan

Ada lebih banyak tentang GitHub. Temukan contoh lengkapnya dan pelajari cara pengaturan dan menjalankannya di Repositori Contoh Kode AWS.

TRY. oo_item = lo_dyn->getitem( iv_tablename = iv_table_name it_key = it_key ). DATA(lt_attr) = oo_item->get_item( ). DATA(lo_title) = lt_attr[ key = 'title' ]-value. DATA(lo_year) = lt_attr[ key = 'year' ]-value. DATA(lo_rating) = lt_attr[ key = 'rating' ]-value. MESSAGE 'Movie name is: ' && lo_title->get_s( ) && 'Movie year is: ' && lo_year->get_n( ) && 'Moving rating is: ' && lo_rating->get_n( ) TYPE 'I'. CATCH /aws1/cx_dynresourcenotfoundex. MESSAGE 'The table or index does not exist' TYPE 'E'. ENDTRY.
  • Untuk API detailnya, lihat GetItem AWSSDKuntuk SAP ABAP API referensi.

Swift
SDKuntuk Swift
catatan

Ada lebih banyak tentang GitHub. Temukan contoh lengkapnya dan pelajari cara pengaturan dan menjalankannya di Repositori Contoh Kode AWS.

import AWSDynamoDB /// Return a `Movie` record describing the specified movie from the Amazon /// DynamoDB table. /// /// - Parameters: /// - title: The movie's title (`String`). /// - year: The movie's release year (`Int`). /// /// - Throws: `MoviesError.ItemNotFound` if the movie isn't in the table. /// /// - Returns: A `Movie` record with the movie's details. func get(title: String, year: Int) async throws -> Movie { do { guard let client = self.ddbClient else { throw MoviesError.UninitializedClient } let input = GetItemInput( key: [ "year": .n(String(year)), "title": .s(title) ], tableName: self.tableName ) let output = try await client.getItem(input: input) guard let item = output.item else { throw MoviesError.ItemNotFound } let movie = try Movie(withItem: item) return movie } catch { print("ERROR: get:", dump(error)) throw error } }
  • Untuk API detailnya, lihat GetItem AWSSDKAPIreferensi Swift.

Untuk daftar lengkap panduan AWS SDK pengembang dan contoh kode, lihatMenggunakan DynamoDB dengan AWS SDK. Topik ini juga mencakup informasi tentang memulai dan detail tentang SDK versi sebelumnya.