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userId (hash key, string)
configId (range key, string)
data (string)
version (Long)
See for example https://github.com/Sage-Bionetworks/BridgeServer2/blob/develop/src/main/java/org/sagebionetworks/bridge/dynamodb/DynamoReportDataDao.java and https://github.com/Sage-Bionetworks/BridgeServer2/blob/develop/src/main/java/org/sagebionetworks/bridge/dynamodb/DynamoReportData.java
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