从 dynamoDB 返回更新的项目

Question

I am using the dynamoDB ExpressionSpecBuilder (Java) to create my update query for an item in the database. I would like the entire modified resource to be returned, without having to specify all attributes inidividually.

Is there a way to do that?

Answer 1

If you are forced to use ExpressionSpecBuilder I couldn't find any way.

However, there are other alternatives like UpdateItemRequest where you can set the ReturnValues property to ALL_NEW and get all attributes as a map:

UpdateItemRequest updateProgramCounterRequest = new UpdateItemRequest()
   .withTableName(...)
   .withUpdateExpression(...)
   .withReturnValues(ReturnValue.ALL_NEW);

UpdateItemResult updateItemResult = amazonDynamoDB.updateItem(updateItemRequest);
Map<String, AttributeValue> attributes = updateItemResult.getAttributes();

Then you can map them to your resource.

A higher level approach is using DynamoDBMapper. Depending on the type of update you need to do, you may also be able to achieve it using save method and modifying the DynamoDBMapperConfig.SaveBehavior property as described on javadoc: https://docs.aws.amazon.com/AWSJavaSDK/latest/javadoc/com/amazonaws/services/dynamodbv2/datamodeling/DynamoDBMapper.html#save-T-com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBSaveExpression-com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMapperConfig-