PROFESSIONAL-CLOUD-DEVELOPER · Question #23
PROFESSIONAL-CLOUD-DEVELOPER Question #23: Real Exam Question with Answer & Explanation
The correct answer is B: Get and put the entity in a transaction.. https://cloud.google.com/datastore/docs/concepts/transactions#uses_for_transactions This requires a transaction because the value of balance in an entity may be updated by another user after this code fetches the object, but before it saves the modified object. Without a transact
Question
Your teammate has asked you to review the code below, which is adding a credit to an account balance in Cloud Datastore. Which improvement should you suggest your teammate make?
Options
- AGet the entity with an ancestor query.
- BGet and put the entity in a transaction.
- CUse a strongly consistent transactional database.
- DDon't return the account entity from the function.
Explanation
https://cloud.google.com/datastore/docs/concepts/transactions#uses_for_transactions This requires a transaction because the value of balance in an entity may be updated by another user after this code fetches the object, but before it saves the modified object. Without a transaction, the user's request uses the value of balance prior to the other user's update, and the save overwrites the new value. With a transaction, the application is told about the other user's
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