1123. Transaction transfer — Hotel — implementation variant 23

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

In a Hotel application, implement this production problem: Transfer money between two accounts atomically. The API/service receives user input and must return or modify data safely. Give the SQL solution, explain why it works, and show how the same operation is called from the selected stack.

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

Option A

DELETE FROM the_table;

Additional Explanation

Incorrect: it does not implement the stated business rule and may modify/fetch the wrong rows.

Verified Correct Answer

Option B

START TRANSACTION; UPDATE accounts SET balance=balance-:amount WHERE id=:from_id AND balance>=:amount; UPDATE accounts SET balance=balance+:amount WHERE id=:to_id; COMMIT;

Additional Explanation

Both writes must succeed as one unit. Application code should verify affected rows and roll back on failure.

Verified

Option C

SELECT * FROM the_table;

Additional Explanation

Incorrect: it does not implement the stated business rule and may modify/fetch the wrong rows.

Verified

Option D

UPDATE the_table SET status='active';

Additional Explanation

Incorrect: it does not implement the stated business rule and may modify/fetch the wrong rows.