使用适用于 PartiQL 的 DynamoDB 执行事务 - Amazon DynamoDB
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使用适用于 PartiQL 的 DynamoDB 执行事务

本节介绍如何将事务与适用于 PartiQL 的 DynamoDB 结合使用。

有关 DynamoDB 事务的更多信息,请参阅使用 DynamoDB 事务管理复杂工作流

注意

整个事务必须由读取语句或写入语句组成;您不能将两者混合在一个事务中。EXISTS 函数是一个例外,可用于以与 ConditionCheckTransactWriteItems API 中的 相似的方式检查项目的特定属性的条件。

Syntax

[ { "Statement":" statement ", "Parameters":[ { " parametertype " : " parametervalue " }, ...] } , ... ]

Parameters

statement

(必需)对于 PartiQL 支持的语句为 DynamoDB。

注意

整个事务必须由读取语句或写入语句组成;您不能将两者混合在一个事务中。

parametertype

(可选) 一个 DynamoDB 类型(如果在指定 PartiQL 语句时使用参数)。

parametervalue

(可选)如果在指定 PartiQL 语句时使用参数,则为参数值。

返回值

此语句不返回任何值。

注意

如果任何单例 INSERT、UPDATE 或 DELETE 操作返回错误,则事务将因 TransactionCanceledException 异常而被取消,并且取消原因代码包括来自单个单例操作的错误。

Examples

AWS CLI
  1. 将以下 json 保存到名为 partiql.json 的文件

    [ { "Statement": "EXISTS(SELECT * FROM Music where Artist='No One You Know' and SongTitle='Call Me Today' and Awards is MISSING)" }, { "Statement": "INSERT INTO Music value {'Artist':'?','SongTitle':'?'}", "Parameters": [{"S": "Acme Band"}, {"S": "Best Song"}] }, { "Statement": "UPDATE Music SET AwardsWon=1 SET AwardDetail={'Grammys':[2020, 2018]} where Artist='Acme Band' and SongTitle='PartiQL Rocks'" } ]
  2. 在命令提示符中执行以下命令。

    aws dynamodb execute-transaction --transact-statements file://partiql.json
Java
public class DynamoDBPartiqlTransaction { public static void main(String[] args) { // Create the DynamoDB Client with the region you want AmazonDynamoDB dynamoDB = createDynamoDbClient("us-west-2"); try { // Create ExecuteTransactionRequest ExecuteTransactionRequest executeTransactionRequest = createExecuteTransactionRequest(); ExecuteTransactionResult executeTransactionResult = dynamoDB.executeTransaction(executeTransactionRequest); System.out.println("ExecuteTransaction successful."); // Handle executeTransactionResult } catch (Exception e) { handleExecuteTransactionErrors(e); } } private static AmazonDynamoDB createDynamoDbClient(String region) { return AmazonDynamoDBClientBuilder.standard().withRegion(region).build(); } private static ExecuteTransactionRequest createExecuteTransactionRequest() { ExecuteTransactionRequest request = new ExecuteTransactionRequest(); // Create statements ListParameterizedStatement> statements = getPartiQLTransactionStatements(); request.setTransactStatements(statements); return request; } private static ListParameterizedStatement> getPartiQLTransactionStatements() { ListParameterizedStatement> statements = new ArrayListParameterizedStatement>(); statements.add(new ParameterizedStatement() .withStatement("EXISTS(SELECT * FROM Music where Artist='No One You Know' and SongTitle='Call Me Today' and Awards is MISSING)")); statements.add(new ParameterizedStatement() .withStatement("INSERT INTO Music value {'Artist':'?','SongTitle':'?'}") .withParameters(new AttributeValue("Acme Band"),new AttributeValue("Best Song"))); statements.add(new ParameterizedStatement() .withStatement("UPDATE Music SET AwardsWon=1 SET AwardDetail={'Grammys':[2020, 2018]} where Artist='Acme Band' and SongTitle='PartiQL Rocks'")); return statements; } // Handles errors during ExecuteTransaction execution. Use recommendations in error messages below to add error handling specific to // your application use-case. private static void handleExecuteTransactionErrors(Exception exception) { try { throw exception; } catch (TransactionCanceledException tce) { System.out.println("Transaction Cancelled, implies a client issue, fix before retrying. Error: " + tce.getErrorMessage()); } catch (TransactionInProgressException tipe) { System.out.println("The transaction with the given request token is already in progress, consider changing " + "retry strategy for this type of error. Error: " + tipe.getErrorMessage()); } catch (IdempotentParameterMismatchException ipme) { System.out.println("Request rejected because it was retried with a different payload but with a request token that was already used, " + "change request token for this payload to be accepted. Error: " + ipme.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()); } } }