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Nozioni di base su PartiQL per DynamoDB
In questa sezione viene descritto come utilizzare PartiQL per DynamoDB dalla console Amazon DynamoDB, da AWS Command Line Interface (AWS CLI) e dalle API DynamoDB.
Nei seguenti esempi, la tabella DynamoDB definita nel tutorial Nozioni di base su DynamoDB è un prerequisito.
Per scaricare e utilizzare NoSQL Workbench per creare istruzioni PartiQL per DynamoDB, seleziona Operazioni PartiQL nell'angolo in alto a destra dell'Operation builder di NoSQL Workbench per DynamoDB.
- Console
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Nel pannello di navigazione sul lato sinistro della console seleziona Editor PartiQL.
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Seleziona la tabella Music.
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Scegli Esegui query sulla tabella. Questa azione genera una query che non determinerà una scansione completa della tabella.
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Sostituisci
partitionKeyValue
con il valore stringaAcme Band
. SostituiscisortKeyValue
con il valore stringaHappy Day
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Scegli il pulsante Esegui.
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È possibile visualizzare i risultati della query scegliendo i pulsanti Vista tabella o Vista JSON.
- NoSQL workbench
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Scegli Istruzione PartiQL.
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Specifica la seguente istruzione SELECT (SELEZIONA) PartiQL.
SELECT * FROM Music WHERE Artist=? and SongTitle=?
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Per specificare un valore per i parametri
Artist
eSongTitle
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Scegli Parametri di richiesta facoltativi.
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Scegli Aggiungi nuovi parametri.
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Scegli il tipo di attributo string e il valore
Acme Band
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Ripeti i passaggi b e c, quindi scegli il tipo string e il valore
PartiQL Rocks
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Per generare codice, selezionare Generate code (Genera codice).
Selezionare la lingua desiderata dalle schede visualizzate. È possibile copiare questo codice e utilizzarlo nell'applicazione.
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Per eseguire l'operazione immediatamente, seleziona Esegui.
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- AWS CLI
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Crea un elemento nella tabella
Music
utilizzando l'istruzione INSERT (INSERISCI) PartiQL.aws dynamodb execute-statement --statement "INSERT INTO Music \ VALUE \ {'Artist':'Acme Band','SongTitle':'PartiQL Rocks'}"
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Recupera un elemento dalla tabella Music utilizzando l'istruzione SELECT (SELEZIONA) PartiQL.
aws dynamodb execute-statement --statement "SELECT * FROM Music \ WHERE Artist='Acme Band' AND SongTitle='PartiQL Rocks'"
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Aggiorna un elemento nella tabella
Music
utilizzando l'istruzione UPDATE (AGGIORNA) PartiQL.aws dynamodb execute-statement --statement "UPDATE Music \ SET AwardsWon=1 \ SET AwardDetail={'Grammys':[2020, 2018]} \ WHERE Artist='Acme Band' AND SongTitle='PartiQL Rocks'"
Aggiungi un valore di elenco per un elemento nella tabella
Music
.aws dynamodb execute-statement --statement "UPDATE Music \ SET AwardDetail.Grammys =list_append(AwardDetail.Grammys,[2016]) \ WHERE Artist='Acme Band' AND SongTitle='PartiQL Rocks'"
Rimuovi un valore di elenco per un elemento nella tabella
Music
.aws dynamodb execute-statement --statement "UPDATE Music \ REMOVE AwardDetail.Grammys[2] \ WHERE Artist='Acme Band' AND SongTitle='PartiQL Rocks'"
Aggiungi un nuovo membro della mappa per un elemento nella tabella
Music
.aws dynamodb execute-statement --statement "UPDATE Music \ SET AwardDetail.BillBoard=[2020] \ WHERE Artist='Acme Band' AND SongTitle='PartiQL Rocks'"
Aggiungi un nuovo attributo del set di stringhe per un elemento nella tabella
Music
.aws dynamodb execute-statement --statement "UPDATE Music \ SET BandMembers =<<'member1', 'member2'>> \ WHERE Artist='Acme Band' AND SongTitle='PartiQL Rocks'"
Aggiungi un attributo del set di stringhe per un elemento nella tabella
Music
.aws dynamodb execute-statement --statement "UPDATE Music \ SET BandMembers =set_add(BandMembers, <<'newmember'>>) \ WHERE Artist='Acme Band' AND SongTitle='PartiQL Rocks'"
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Elimina un elemento dalla tabella
Music
utilizzando l'istruzione DELETE (ELIMINA) PartiQL.aws dynamodb execute-statement --statement "DELETE FROM Music \ WHERE Artist='Acme Band' AND SongTitle='PartiQL Rocks'"
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- Java
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import java.util.ArrayList; import java.util.List; import com.amazonaws.AmazonClientException; import com.amazonaws.AmazonServiceException; import com.amazonaws.services.dynamodbv2.AmazonDynamoDB; import com.amazonaws.services.dynamodbv2.AmazonDynamoDBClientBuilder; import com.amazonaws.services.dynamodbv2.model.AttributeValue; import com.amazonaws.services.dynamodbv2.model.ConditionalCheckFailedException; import com.amazonaws.services.dynamodbv2.model.ExecuteStatementRequest; import com.amazonaws.services.dynamodbv2.model.ExecuteStatementResult; import com.amazonaws.services.dynamodbv2.model.InternalServerErrorException; import com.amazonaws.services.dynamodbv2.model.ItemCollectionSizeLimitExceededException; import com.amazonaws.services.dynamodbv2.model.ProvisionedThroughputExceededException; import com.amazonaws.services.dynamodbv2.model.RequestLimitExceededException; import com.amazonaws.services.dynamodbv2.model.ResourceNotFoundException; import com.amazonaws.services.dynamodbv2.model.TransactionConflictException; public class DynamoDBPartiQGettingStarted { public static void main(String[] args) { // Create the DynamoDB Client with the region you want AmazonDynamoDB dynamoDB = createDynamoDbClient("us-west-1"); try { // Create ExecuteStatementRequest ExecuteStatementRequest executeStatementRequest = new ExecuteStatementRequest(); List<AttributeValue> parameters= getPartiQLParameters(); //Create an item in the Music table using the INSERT PartiQL statement processResults(executeStatementRequest(dynamoDB, "INSERT INTO Music value {'Artist':?,'SongTitle':?}", parameters)); //Retrieve an item from the Music table using the SELECT PartiQL statement. processResults(executeStatementRequest(dynamoDB, "SELECT * FROM Music where Artist=? and SongTitle=?", parameters)); //Update an item in the Music table using the UPDATE PartiQL statement. processResults(executeStatementRequest(dynamoDB, "UPDATE Music SET AwardsWon=1 SET AwardDetail={'Grammys':[2020, 2018]} where Artist=? and SongTitle=?", parameters)); //Add a list value for an item in the Music table. processResults(executeStatementRequest(dynamoDB, "UPDATE Music SET AwardDetail.Grammys =list_append(AwardDetail.Grammys,[2016]) where Artist=? and SongTitle=?", parameters)); //Remove a list value for an item in the Music table. processResults(executeStatementRequest(dynamoDB, "UPDATE Music REMOVE AwardDetail.Grammys[2] where Artist=? and SongTitle=?", parameters)); //Add a new map member for an item in the Music table. processResults(executeStatementRequest(dynamoDB, "UPDATE Music set AwardDetail.BillBoard=[2020] where Artist=? and SongTitle=?", parameters)); //Add a new string set attribute for an item in the Music table. processResults(executeStatementRequest(dynamoDB, "UPDATE Music SET BandMembers =<<'member1', 'member2'>> where Artist=? and SongTitle=?", parameters)); //update a string set attribute for an item in the Music table. processResults(executeStatementRequest(dynamoDB, "UPDATE Music SET BandMembers =set_add(BandMembers, <<'newmember'>>) where Artist=? and SongTitle=?", parameters)); //Retrieve an item from the Music table using the SELECT PartiQL statement. processResults(executeStatementRequest(dynamoDB, "SELECT * FROM Music where Artist=? and SongTitle=?", parameters)); //delete an item from the Music Table processResults(executeStatementRequest(dynamoDB, "DELETE FROM Music where Artist=? and SongTitle=?", parameters)); } catch (Exception e) { handleExecuteStatementErrors(e); } } private static AmazonDynamoDB createDynamoDbClient(String region) { return AmazonDynamoDBClientBuilder.standard().withRegion(region).build(); } private static List<AttributeValue> getPartiQLParameters() { List<AttributeValue> parameters = new ArrayList<AttributeValue>(); parameters.add(new AttributeValue("Acme Band")); parameters.add(new AttributeValue("PartiQL Rocks")); return parameters; } private static ExecuteStatementResult executeStatementRequest(AmazonDynamoDB client, String statement, List<AttributeValue> parameters ) { ExecuteStatementRequest request = new ExecuteStatementRequest(); request.setStatement(statement); request.setParameters(parameters); return client.executeStatement(request); } private static void processResults(ExecuteStatementResult executeStatementResult) { System.out.println("ExecuteStatement successful: "+ executeStatementResult.toString()); } // Handles errors during ExecuteStatement execution. Use recommendations in error messages below to add error handling specific to // your application use-case. private static void handleExecuteStatementErrors(Exception exception) { try { throw exception; } catch (ConditionalCheckFailedException ccfe) { System.out.println("Condition check specified in the operation failed, review and update the condition " + "check before retrying. Error: " + ccfe.getErrorMessage()); } catch (TransactionConflictException tce) { System.out.println("Operation was rejected because there is an ongoing transaction for the item, generally " + "safe to retry with exponential back-off. Error: " + tce.getErrorMessage()); } catch (ItemCollectionSizeLimitExceededException icslee) { System.out.println("An item collection is too large, you\'re using Local Secondary Index and exceeded " + "size limit of items per partition key. Consider using Global Secondary Index instead. Error: " + icslee.getErrorMessage()); } catch (Exception e) { handleCommonErrors(e); } } private static void handleCommonErrors(Exception exception) { try { throw exception; } catch (InternalServerErrorException isee) { System.out.println("Internal Server Error, generally safe to retry with exponential back-off. Error: " + isee.getErrorMessage()); } catch (RequestLimitExceededException rlee) { System.out.println("Throughput exceeds the current throughput limit for your account, increase account level throughput before " + "retrying. Error: " + rlee.getErrorMessage()); } catch (ProvisionedThroughputExceededException ptee) { System.out.println("Request rate is too high. If you're using a custom retry strategy make sure to retry with exponential back-off. " + "Otherwise consider reducing frequency of requests or increasing provisioned capacity for your table or secondary index. Error: " + ptee.getErrorMessage()); } catch (ResourceNotFoundException rnfe) { System.out.println("One of the tables was not found, verify table exists before retrying. Error: " + rnfe.getErrorMessage()); } catch (AmazonServiceException ase) { System.out.println("An AmazonServiceException occurred, indicates that the request was correctly transmitted to the DynamoDB " + "service, but for some reason, the service was not able to process it, and returned an error response instead. Investigate and " + "configure retry strategy. Error type: " + ase.getErrorType() + ". Error message: " + ase.getErrorMessage()); } catch (AmazonClientException ace) { System.out.println("An AmazonClientException occurred, indicates that the client was unable to get a response from DynamoDB " + "service, or the client was unable to parse the response from the service. Investigate and configure retry strategy. "+ "Error: " + ace.getMessage()); } catch (Exception e) { System.out.println("An exception occurred, investigate and configure retry strategy. Error: " + e.getMessage()); } } }