3512. Education: Find the highest scorer in every class. — Transactions

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

In a education module, solve this as a production problem using Transactions: Find the highest scorer in every class. Provide the SQL, explain the logic, show safe application integration, and mention failure/edge cases.

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Answer & Explanation

4 Answers

Verified

Option A

SELECT * FROM table_name;

Additional Explanation

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

Verified Correct Answer

Option B

SELECT * FROM (SELECT s.*,RANK() OVER(PARTITION BY class_id ORDER BY marks DESC) rnk FROM students s) x WHERE rnk=1;

Additional Explanation

RANK preserves ties; use ROW_NUMBER if exactly one row is required.

Verified

Option C

UPDATE table_name SET status='active';

Additional Explanation

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

Verified

Option D

DELETE FROM table_name;

Additional Explanation

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