We have learned enough about DynamoDB to create a backend for a serverless application. You can learn further from AWS documentation. You may also follow my notes on DynamoDB at http://cloudmaterials.com/en/book/amazon-dynamo-db-essentials.
Following are some useful links to AWS documentation:
- https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/JavaDocumentAPIItemCRUD.html
- https://docs.aws.amazon.com/sdk-for-java/v1/developer-guide/examples-dynamodb-items.html
- https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ScanJavaDocumentAPI.html
- https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/QueryingJavaDocumentAPI.html
- https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.ExpressionAttributeNames.html