2395. Messaging: Mark all unread messages in a conversation as read. — Python + FastAPI + SQLAlchemy

DBMS Published 30 Sept 2026 Updated 30 Sept 2026 0 Views Verified

In a messaging module, solve this as a production problem using Python + FastAPI + SQLAlchemy: Mark all unread messages in a conversation as read. Provide the SQL, explain the logic, show safe application integration, and mention failure/edge cases.

Looking for the latest Sarkari Result 2026 updates? Check the latest government exam results, merit lists and result updates on Sarkari Resultess.

Answer & Explanation

4 Answers

Verified Correct Answer

Option A

UPDATE messages SET read_at=CURRENT_TIMESTAMP WHERE conversation_id=:conversation_id AND recipient_id=:user_id AND read_at IS NULL;

Additional Explanation

Recipient filtering prevents one user from marking another user's messages as read.

Verified

Option B

DELETE FROM table_name;

Additional Explanation

Incorrect: it does not satisfy the stated business rule and can return/change unintended data.

Verified

Option C

SELECT * FROM table_name;

Additional Explanation

Incorrect: it does not satisfy the stated business rule and can return/change unintended data.

Verified

Option D

UPDATE table_name SET status='active';

Additional Explanation

Incorrect: it does not satisfy the stated business rule and can return/change unintended data.