Question

A developer is building an online banking feature that transfers funds between two accounts stored as separate items in a single DynamoDB table. Both the debit on the source account item and the credit on the destination account item must either both succeed or both fail, with no partial updates visible to other readers. Which approach should the developer use?

Accepted Answer

Use a single TransactWriteItems call containing both the debit and credit update operations.

Answer

Issue two separate UpdateItem calls and roll back the first if the second fails.

Answer

Use BatchWriteItem to submit both PutItem operations in one request.

Answer

Enable DynamoDB Streams and use a Lambda function to reconcile the two items after each write.