Da utilizzare UpdateItem con un AWS SDK o CLI - Amazon DynamoDB

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Da utilizzare UpdateItem con un AWS SDK o CLI

I seguenti esempi di codice mostrano come utilizzareUpdateItem.

Gli esempi di operazioni sono estratti di codice da programmi più grandi e devono essere eseguiti nel contesto. È possibile visualizzare questa operazione nel contesto nei seguenti esempi di codice:

.NET
AWS SDK for .NET
Nota

C'è altro su. GitHub Trova l'esempio completo e scopri di più sulla configurazione e l'esecuzione nel Repository di esempi di codice AWS.

/// <summary> /// Updates an existing item in the movies table. /// </summary> /// <param name="client">An initialized Amazon DynamoDB client object.</param> /// <param name="newMovie">A Movie object containing information for /// the movie to update.</param> /// <param name="newInfo">A MovieInfo object that contains the /// information that will be changed.</param> /// <param name="tableName">The name of the table that contains the movie.</param> /// <returns>A Boolean value that indicates the success of the operation.</returns> public static async Task<bool> UpdateItemAsync( AmazonDynamoDBClient client, Movie newMovie, MovieInfo newInfo, string tableName) { var key = new Dictionary<string, AttributeValue> { ["title"] = new AttributeValue { S = newMovie.Title }, ["year"] = new AttributeValue { N = newMovie.Year.ToString() }, }; var updates = new Dictionary<string, AttributeValueUpdate> { ["info.plot"] = new AttributeValueUpdate { Action = AttributeAction.PUT, Value = new AttributeValue { S = newInfo.Plot }, }, ["info.rating"] = new AttributeValueUpdate { Action = AttributeAction.PUT, Value = new AttributeValue { N = newInfo.Rank.ToString() }, }, }; var request = new UpdateItemRequest { AttributeUpdates = updates, Key = key, TableName = tableName, }; var response = await client.UpdateItemAsync(request); return response.HttpStatusCode == System.Net.HttpStatusCode.OK; }
Bash
AWS CLI con lo script Bash
Nota

C'è altro da fare. GitHub Trova l'esempio completo e scopri di più sulla configurazione e l'esecuzione nel Repository di esempi di codice AWS.

############################################################################## # function dynamodb_update_item # # This function updates an item in 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 update. # -e update expression -- An expression that defines one or more attributes to be updated. # -v values -- Path to json file containing the update values. # # Returns: # 0 - If successful. # 1 - If it fails. ############################################################################# function dynamodb_update_item() { local table_name keys update_expression values response local option OPTARG # Required to use getopts command in a function. ####################################### # Function usage explanation ####################################### function usage() { echo "function dynamodb_update_item" echo "Update an item in 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 update." echo " -e update expression -- An expression that defines one or more attributes to be updated." echo " -v values -- Path to json file containing the update values." echo "" } while getopts "n:k:e:v:h" option; do case "${option}" in n) table_name="${OPTARG}" ;; k) keys="${OPTARG}" ;; e) update_expression="${OPTARG}" ;; v) values="${OPTARG}" ;; h) usage return 0 ;; \?) echo "Invalid parameter" usage return 1 ;; esac done export OPTIND=1 if [[ -z "$table_name" ]]; then errecho "ERROR: You must provide a table name with the -n parameter." usage return 1 fi if [[ -z "$keys" ]]; then errecho "ERROR: You must provide a keys json file path the -k parameter." usage return 1 fi if [[ -z "$update_expression" ]]; then errecho "ERROR: You must provide an update expression with the -e parameter." usage return 1 fi if [[ -z "$values" ]]; then errecho "ERROR: You must provide a values json file path the -v parameter." usage return 1 fi iecho "Parameters:\n" iecho " table_name: $table_name" iecho " keys: $keys" iecho " update_expression: $update_expression" iecho " values: $values" response=$(aws dynamodb update-item \ --table-name "$table_name" \ --key file://"$keys" \ --update-expression "$update_expression" \ --expression-attribute-values file://"$values") local error_code=${?} if [[ $error_code -ne 0 ]]; then aws_cli_error_log $error_code errecho "ERROR: AWS reports update-item operation failed.$response" return 1 fi return 0 }

Le funzioni di utilità utilizzate in questo esempio.

############################################################################### # function iecho # # This function enables the script to display the specified text only if # the global variable $VERBOSE is set to true. ############################################################################### function iecho() { if [[ $VERBOSE == true ]]; then echo "$@" fi } ############################################################################### # 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 }
  • Per API i dettagli, vedere UpdateItemin AWS CLI Command Reference.

C++
SDKper C++
Nota

C'è di più su. GitHub Trova l'esempio completo e scopri di più sulla configurazione e l'esecuzione nel Repository di esempi di codice AWS.

//! Update an Amazon DynamoDB table item. /*! \sa updateItem() \param tableName: The table name. \param partitionKey: The partition key. \param partitionValue: The value for the partition key. \param attributeKey: The key for the attribute to be updated. \param attributeValue: The value for the attribute to be updated. \param clientConfiguration: AWS client configuration. \return bool: Function succeeded. */ /* * The example code only sets/updates an attribute value. It processes * the attribute value as a string, even if the value could be interpreted * as a number. Also, the example code does not remove an existing attribute * from the key value. */ bool AwsDoc::DynamoDB::updateItem(const Aws::String &tableName, const Aws::String &partitionKey, const Aws::String &partitionValue, const Aws::String &attributeKey, const Aws::String &attributeValue, const Aws::Client::ClientConfiguration &clientConfiguration) { Aws::DynamoDB::DynamoDBClient dynamoClient(clientConfiguration); // *** Define UpdateItem request arguments. // Define TableName argument. Aws::DynamoDB::Model::UpdateItemRequest request; request.SetTableName(tableName); // Define KeyName argument. Aws::DynamoDB::Model::AttributeValue attribValue; attribValue.SetS(partitionValue); request.AddKey(partitionKey, attribValue); // Construct the SET update expression argument. Aws::String update_expression("SET #a = :valueA"); request.SetUpdateExpression(update_expression); // Construct attribute name argument. Aws::Map<Aws::String, Aws::String> expressionAttributeNames; expressionAttributeNames["#a"] = attributeKey; request.SetExpressionAttributeNames(expressionAttributeNames); // Construct attribute value argument. Aws::DynamoDB::Model::AttributeValue attributeUpdatedValue; attributeUpdatedValue.SetS(attributeValue); Aws::Map<Aws::String, Aws::DynamoDB::Model::AttributeValue> expressionAttributeValues; expressionAttributeValues[":valueA"] = attributeUpdatedValue; request.SetExpressionAttributeValues(expressionAttributeValues); // Update the item. const Aws::DynamoDB::Model::UpdateItemOutcome &outcome = dynamoClient.UpdateItem( request); if (outcome.IsSuccess()) { std::cout << "Item was updated" << std::endl; } else { std::cerr << outcome.GetError().GetMessage() << std::endl; return false; } return waitTableActive(tableName, dynamoClient); }

Codice che attende che la tabella diventi attiva.

//! Query a newly created DynamoDB table until it is active. /*! \sa waitTableActive() \param waitTableActive: The DynamoDB table's name. \param dynamoClient: A DynamoDB client. \return bool: Function succeeded. */ bool AwsDoc::DynamoDB::waitTableActive(const Aws::String &tableName, const Aws::DynamoDB::DynamoDBClient &dynamoClient) { // Repeatedly call DescribeTable until table is ACTIVE. const int MAX_QUERIES = 20; Aws::DynamoDB::Model::DescribeTableRequest request; request.SetTableName(tableName); int count = 0; while (count < MAX_QUERIES) { const Aws::DynamoDB::Model::DescribeTableOutcome &result = dynamoClient.DescribeTable( request); if (result.IsSuccess()) { Aws::DynamoDB::Model::TableStatus status = result.GetResult().GetTable().GetTableStatus(); if (Aws::DynamoDB::Model::TableStatus::ACTIVE != status) { std::this_thread::sleep_for(std::chrono::seconds(1)); } else { return true; } } else { std::cerr << "Error DynamoDB::waitTableActive " << result.GetError().GetMessage() << std::endl; return false; } count++; } return false; }
  • Per API i dettagli, vedere UpdateItemin AWS SDK for C++ APIReference.

CLI
AWS CLI

Esempio 1: aggiornare un elemento in una tabella

L'esempio update-item seguente legge una voce dalla tabella MusicCollection. Aggiunge un nuovo attributo (Year) e modifica l'AlbumTitleattributo. Tutti gli attributi dell'elemento, così come appaiono dopo l'aggiornamento, vengono restituiti nella risposta.

aws dynamodb update-item \ --table-name MusicCollection \ --key file://key.json \ --update-expression "SET #Y = :y, #AT = :t" \ --expression-attribute-names file://expression-attribute-names.json \ --expression-attribute-values file://expression-attribute-values.json \ --return-values ALL_NEW \ --return-consumed-capacity TOTAL \ --return-item-collection-metrics SIZE

Contenuto di key.json.

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

Contenuto di expression-attribute-names.json.

{ "#Y":"Year", "#AT":"AlbumTitle" }

Contenuto di expression-attribute-values.json.

{ ":y":{"N": "2015"}, ":t":{"S": "Louder Than Ever"} }

Output:

{ "Attributes": { "AlbumTitle": { "S": "Louder Than Ever" }, "Awards": { "N": "10" }, "Artist": { "S": "Acme Band" }, "Year": { "N": "2015" }, "SongTitle": { "S": "Happy Day" } }, "ConsumedCapacity": { "TableName": "MusicCollection", "CapacityUnits": 3.0 }, "ItemCollectionMetrics": { "ItemCollectionKey": { "Artist": { "S": "Acme Band" } }, "SizeEstimateRangeGB": [ 0.0, 1.0 ] } }

Per ulteriori informazioni, consulta Writing an Item in Amazon DynamoDB Developer Guide.

Esempio 2: aggiornare un articolo in modo condizionale

L'esempio seguente aggiorna un elemento nella MusicCollection tabella, ma solo se l'elemento esistente non ha già un Year attributo.

aws dynamodb update-item \ --table-name MusicCollection \ --key file://key.json \ --update-expression "SET #Y = :y, #AT = :t" \ --expression-attribute-names file://expression-attribute-names.json \ --expression-attribute-values file://expression-attribute-values.json \ --condition-expression "attribute_not_exists(#Y)"

Contenuto di key.json.

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

Contenuto di expression-attribute-names.json.

{ "#Y":"Year", "#AT":"AlbumTitle" }

Contenuto di expression-attribute-values.json.

{ ":y":{"N": "2015"}, ":t":{"S": "Louder Than Ever"} }

Se l'elemento ha già un Year attributo, DynamoDB restituisce il seguente output.

An error occurred (ConditionalCheckFailedException) when calling the UpdateItem operation: The conditional request failed

Per ulteriori informazioni, consulta Writing an Item in Amazon DynamoDB Developer Guide.

  • Per API i dettagli, consulta AWS CLI Command UpdateItemReference.

Go
SDKper Go V2
Nota

C'è altro da fare. GitHub Trova l'esempio completo e scopri di più sulla configurazione e l'esecuzione nel Repository di esempi di codice 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 } // UpdateMovie updates the rating and plot of a movie that already exists in the // DynamoDB table. This function uses the `expression` package to build the update // expression. func (basics TableBasics) UpdateMovie(ctx context.Context, movie Movie) (map[string]map[string]interface{}, error) { var err error var response *dynamodb.UpdateItemOutput var attributeMap map[string]map[string]interface{} update := expression.Set(expression.Name("info.rating"), expression.Value(movie.Info["rating"])) update.Set(expression.Name("info.plot"), expression.Value(movie.Info["plot"])) expr, err := expression.NewBuilder().WithUpdate(update).Build() if err != nil { log.Printf("Couldn't build expression for update. Here's why: %v\n", err) } else { response, err = basics.DynamoDbClient.UpdateItem(ctx, &dynamodb.UpdateItemInput{ TableName: aws.String(basics.TableName), Key: movie.GetKey(), ExpressionAttributeNames: expr.Names(), ExpressionAttributeValues: expr.Values(), UpdateExpression: expr.Update(), ReturnValues: types.ReturnValueUpdatedNew, }) if err != nil { log.Printf("Couldn't update movie %v. Here's why: %v\n", movie.Title, err) } else { err = attributevalue.UnmarshalMap(response.Attributes, &attributeMap) if err != nil { log.Printf("Couldn't unmarshall update response. Here's why: %v\n", err) } } } return attributeMap, 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"]) }
Java
SDKper Java 2.x
Nota

C'è di più su. GitHub Trova l'esempio completo e scopri di più sulla configurazione e l'esecuzione nel Repository di esempi di codice AWS.

Aggiorna un elemento in una tabella utilizzando DynamoDbClient.

import software.amazon.awssdk.regions.Region; import software.amazon.awssdk.services.dynamodb.model.DynamoDbException; import software.amazon.awssdk.services.dynamodb.model.AttributeAction; import software.amazon.awssdk.services.dynamodb.model.AttributeValue; import software.amazon.awssdk.services.dynamodb.model.AttributeValueUpdate; import software.amazon.awssdk.services.dynamodb.model.UpdateItemRequest; import software.amazon.awssdk.services.dynamodb.DynamoDbClient; import java.util.HashMap; /** * 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 update an Amazon DynamoDB table using the AWS SDK for Java V2, its better * practice to use the * Enhanced Client, See the EnhancedModifyItem example. */ public class UpdateItem { public static void main(String[] args) { final String usage = """ Usage: <tableName> <key> <keyVal> <name> <updateVal> Where: tableName - The Amazon DynamoDB table (for example, Music3). key - The name of the key in the table (for example, Artist). keyVal - The value of the key (for example, Famous Band). name - The name of the column where the value is updated (for example, Awards). updateVal - The value used to update an item (for example, 14). Example: UpdateItem Music3 Artist Famous Band Awards 14 """; if (args.length != 5) { System.out.println(usage); System.exit(1); } String tableName = args[0]; String key = args[1]; String keyVal = args[2]; String name = args[3]; String updateVal = args[4]; Region region = Region.US_EAST_1; DynamoDbClient ddb = DynamoDbClient.builder() .region(region) .build(); updateTableItem(ddb, tableName, key, keyVal, name, updateVal); ddb.close(); } public static void updateTableItem(DynamoDbClient ddb, String tableName, String key, String keyVal, String name, String updateVal) { HashMap<String, AttributeValue> itemKey = new HashMap<>(); itemKey.put(key, AttributeValue.builder() .s(keyVal) .build()); HashMap<String, AttributeValueUpdate> updatedValues = new HashMap<>(); updatedValues.put(name, AttributeValueUpdate.builder() .value(AttributeValue.builder().s(updateVal).build()) .action(AttributeAction.PUT) .build()); UpdateItemRequest request = UpdateItemRequest.builder() .tableName(tableName) .key(itemKey) .attributeUpdates(updatedValues) .build(); try { ddb.updateItem(request); } catch (DynamoDbException e) { System.err.println(e.getMessage()); System.exit(1); } System.out.println("The Amazon DynamoDB table was updated!"); } }
  • Per API i dettagli, vedere UpdateItemin AWS SDK for Java 2.x APIReference.

JavaScript
SDKper JavaScript (v3)
Nota

C'è di più su. GitHub Trova l'esempio completo e scopri di più sulla configurazione e l'esecuzione nel Repository di esempi di codice AWS.

Questo esempio utilizza il client di documenti per semplificare il lavoro con gli elementi in DynamoDB. Per API i dettagli vedi UpdateCommand.

import { DynamoDBClient } from "@aws-sdk/client-dynamodb"; import { DynamoDBDocumentClient, UpdateCommand } from "@aws-sdk/lib-dynamodb"; const client = new DynamoDBClient({}); const docClient = DynamoDBDocumentClient.from(client); export const main = async () => { const command = new UpdateCommand({ TableName: "Dogs", Key: { Breed: "Labrador", }, UpdateExpression: "set Color = :color", ExpressionAttributeValues: { ":color": "black", }, ReturnValues: "ALL_NEW", }); const response = await docClient.send(command); console.log(response); return response; };
  • Per API i dettagli, vedere UpdateItemin AWS SDK for JavaScript APIReference.

Kotlin
SDKper Kotlin
Nota

c'è altro da fare. GitHub Trova l'esempio completo e scopri di più sulla configurazione e l'esecuzione nel Repository di esempi di codice AWS.

suspend fun updateTableItem( tableNameVal: String, keyName: String, keyVal: String, name: String, updateVal: String, ) { val itemKey = mutableMapOf<String, AttributeValue>() itemKey[keyName] = AttributeValue.S(keyVal) val updatedValues = mutableMapOf<String, AttributeValueUpdate>() updatedValues[name] = AttributeValueUpdate { value = AttributeValue.S(updateVal) action = AttributeAction.Put } val request = UpdateItemRequest { tableName = tableNameVal key = itemKey attributeUpdates = updatedValues } DynamoDbClient { region = "us-east-1" }.use { ddb -> ddb.updateItem(request) println("Item in $tableNameVal was updated") } }
  • Per API i dettagli, vedi il riferimento UpdateItem AWSSDKa Kotlin API.

PHP
SDK per PHP
Nota

C'è altro su. GitHub Trova l'esempio completo e scopri di più sulla configurazione e l'esecuzione nel Repository di esempi di codice AWS.

echo "What rating would you like to give {$movie['Item']['title']['S']}?\n"; $rating = 0; while (!is_numeric($rating) || intval($rating) != $rating || $rating < 1 || $rating > 10) { $rating = testable_readline("Rating (1-10): "); } $service->updateItemAttributeByKey($tableName, $key, 'rating', 'N', $rating); public function updateItemAttributeByKey( string $tableName, array $key, string $attributeName, string $attributeType, string $newValue ) { $this->dynamoDbClient->updateItem([ 'Key' => $key['Item'], 'TableName' => $tableName, 'UpdateExpression' => "set #NV=:NV", 'ExpressionAttributeNames' => [ '#NV' => $attributeName, ], 'ExpressionAttributeValues' => [ ':NV' => [ $attributeType => $newValue ] ], ]); }
PowerShell
Strumenti per PowerShell

Esempio 1: imposta l'attributo genre su 'Rap' sull'elemento DynamoDB con la chiave di partizione e la SongTitle chiave di ordinamento Artist.

$key = @{ SongTitle = 'Somewhere Down The Road' Artist = 'No One You Know' } | ConvertTo-DDBItem $updateDdbItem = @{ TableName = 'Music' Key = $key UpdateExpression = 'set Genre = :val1' ExpressionAttributeValue = (@{ ':val1' = ([Amazon.DynamoDBv2.Model.AttributeValue]'Rap') }) } Update-DDBItem @updateDdbItem

Output:

Name Value ---- ----- Genre Rap
  • Per API i dettagli, vedere UpdateItemin AWS Tools for PowerShell Cmdlet Reference.

Python
SDKper Python (Boto3)
Nota

C'è di più su. GitHub Trova l'esempio completo e scopri di più sulla configurazione e l'esecuzione nel Repository di esempi di codice AWS.

Aggiorna un elemento utilizzando un’espressione di aggiornamento.

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 update_movie(self, title, year, rating, plot): """ Updates rating and plot data for a movie in the table. :param title: The title of the movie to update. :param year: The release year of the movie to update. :param rating: The updated rating to the give the movie. :param plot: The updated plot summary to give the movie. :return: The fields that were updated, with their new values. """ try: response = self.table.update_item( Key={"year": year, "title": title}, UpdateExpression="set info.rating=:r, info.plot=:p", ExpressionAttributeValues={":r": Decimal(str(rating)), ":p": plot}, ReturnValues="UPDATED_NEW", ) except ClientError as err: logger.error( "Couldn't update movie %s in table %s. Here's why: %s: %s", title, self.table.name, err.response["Error"]["Code"], err.response["Error"]["Message"], ) raise else: return response["Attributes"]

Aggiorna un elemento utilizzando un'espressione di aggiornamento che include un'operazione aritmetica.

class UpdateQueryWrapper: def __init__(self, table): self.table = table def update_rating(self, title, year, rating_change): """ Updates the quality rating of a movie in the table by using an arithmetic operation in the update expression. By specifying an arithmetic operation, you can adjust a value in a single request, rather than first getting its value and then setting its new value. :param title: The title of the movie to update. :param year: The release year of the movie to update. :param rating_change: The amount to add to the current rating for the movie. :return: The updated rating. """ try: response = self.table.update_item( Key={"year": year, "title": title}, UpdateExpression="set info.rating = info.rating + :val", ExpressionAttributeValues={":val": Decimal(str(rating_change))}, ReturnValues="UPDATED_NEW", ) except ClientError as err: logger.error( "Couldn't update movie %s in table %s. Here's why: %s: %s", title, self.table.name, err.response["Error"]["Code"], err.response["Error"]["Message"], ) raise else: return response["Attributes"]

Aggiorna un elemento solo quando soddisfa determinate condizioni.

class UpdateQueryWrapper: def __init__(self, table): self.table = table def remove_actors(self, title, year, actor_threshold): """ Removes an actor from a movie, but only when the number of actors is greater than a specified threshold. If the movie does not list more than the threshold, no actors are removed. :param title: The title of the movie to update. :param year: The release year of the movie to update. :param actor_threshold: The threshold of actors to check. :return: The movie data after the update. """ try: response = self.table.update_item( Key={"year": year, "title": title}, UpdateExpression="remove info.actors[0]", ConditionExpression="size(info.actors) > :num", ExpressionAttributeValues={":num": actor_threshold}, ReturnValues="ALL_NEW", ) except ClientError as err: if err.response["Error"]["Code"] == "ConditionalCheckFailedException": logger.warning( "Didn't update %s because it has fewer than %s actors.", title, actor_threshold + 1, ) else: logger.error( "Couldn't update movie %s. Here's why: %s: %s", title, err.response["Error"]["Code"], err.response["Error"]["Message"], ) raise else: return response["Attributes"]
  • Per API i dettagli, vedere UpdateItemPython (Boto3) Reference.AWS SDK API

Ruby
SDKper Ruby
Nota

c'è altro da fare. GitHub Trova l'esempio completo e scopri di più sulla configurazione e l'esecuzione nel Repository di esempi di codice 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 # Updates rating and plot data for a movie in the table. # # @param movie [Hash] The title, year, plot, rating of the movie. def update_item(movie) response = @table.update_item( key: { 'year' => movie[:year], 'title' => movie[:title] }, update_expression: 'set info.rating=:r', expression_attribute_values: { ':r' => movie[:rating] }, return_values: 'UPDATED_NEW' ) rescue Aws::DynamoDB::Errors::ServiceError => e puts("Couldn't update movie #{movie[:title]} (#{movie[:year]}) in table #{@table.name}\n") puts("\t#{e.code}: #{e.message}") raise else response.attributes end
SAP ABAP
SDKper SAP ABAP
Nota

C'è altro da fare GitHub. Trova l'esempio completo e scopri di più sulla configurazione e l'esecuzione nel Repository di esempi di codice AWS.

TRY. oo_output = lo_dyn->updateitem( iv_tablename = iv_table_name it_key = it_item_key it_attributeupdates = it_attribute_updates ). MESSAGE '1 item updated in DynamoDB Table' && iv_table_name TYPE 'I'. CATCH /aws1/cx_dyncondalcheckfaile00. MESSAGE 'A condition specified in the operation could not be evaluated.' TYPE 'E'. CATCH /aws1/cx_dynresourcenotfoundex. MESSAGE 'The table or index does not exist' TYPE 'E'. CATCH /aws1/cx_dyntransactconflictex. MESSAGE 'Another transaction is using the item' TYPE 'E'. ENDTRY.
  • Per API i dettagli, vedi UpdateItemSAPABAPAPIcome riferimento.AWS SDK

Swift
SDKper Swift
Nota

c'è altro da fare. GitHub Trova l'esempio completo e scopri di più sulla configurazione e l'esecuzione nel Repository di esempi di codice AWS.

import AWSDynamoDB /// Update the specified movie with new `rating` and `plot` information. /// /// - Parameters: /// - title: The title of the movie to update. /// - year: The release year of the movie to update. /// - rating: The new rating for the movie. /// - plot: The new plot summary string for the movie. /// /// - Returns: An array of mappings of attribute names to their new /// listing each item actually changed. Items that didn't need to change /// aren't included in this list. `nil` if no changes were made. /// func update(title: String, year: Int, rating: Double? = nil, plot: String? = nil) async throws -> [Swift.String: DynamoDBClientTypes.AttributeValue]? { do { guard let client = self.ddbClient else { throw MoviesError.UninitializedClient } // Build the update expression and the list of expression attribute // values. Include only the information that's changed. var expressionParts: [String] = [] var attrValues: [Swift.String: DynamoDBClientTypes.AttributeValue] = [:] if rating != nil { expressionParts.append("info.rating=:r") attrValues[":r"] = .n(String(rating!)) } if plot != nil { expressionParts.append("info.plot=:p") attrValues[":p"] = .s(plot!) } let expression = "set \(expressionParts.joined(separator: ", "))" let input = UpdateItemInput( // Create substitution tokens for the attribute values, to ensure // no conflicts in expression syntax. expressionAttributeValues: attrValues, // The key identifying the movie to update consists of the release // year and title. key: [ "year": .n(String(year)), "title": .s(title) ], returnValues: .updatedNew, tableName: self.tableName, updateExpression: expression ) let output = try await client.updateItem(input: input) guard let attributes: [Swift.String: DynamoDBClientTypes.AttributeValue] = output.attributes else { throw MoviesError.InvalidAttributes } return attributes } catch { print("ERROR: update:", dump(error)) throw error } }
  • Per API i dettagli, consulta la sezione UpdateItem AWSSDKdi API riferimento di Swift.

Per un elenco completo di guide per AWS SDK sviluppatori ed esempi di codice, consultaUsare DynamoDB con AWS SDK. Questo argomento include anche informazioni su come iniziare e dettagli sulle SDK versioni precedenti.