Main transaction controls?
Interviewer Expectations for this Question
01
Core Competency
Assesses fundamental understanding of SQL & Databases conventions, runtime behavior, and memory/performance considerations.
02
Evaluation Criteria
Hiring managers look for precision, avoidance of ambiguous jargon, and ability to explain trade-offs under real production conditions.
Comprehensive Model Answer
Verified Solution
COMMIT— Make changes permanentROLLBACK— Undo all changes in the transactionSAVEPOINT— Set a partial rollback point
START TRANSACTION;
UPDATE accounts SET balance = balance - 100 WHERE id = 1;
SAVEPOINT before_credit;
UPDATE accounts SET balance = balance + 100 WHERE id = 2;
-- Oops, wrong account!
ROLLBACK TO SAVEPOINT before_credit;
-- Now retry with correct account
COMMIT;
Candidate Response Strategy & Interview Tips
- Start with a concise one-sentence summary: Deliver a direct, confident answer first before expanding into nuances.
- Demonstrate real-world trade-offs: Discuss where this approach excels and when you would avoid it in production systems.
- Discuss complexity & edge cases: Proactively explain time/space complexity or boundary conditions (null values, scale limits).
- Prepare for interviewer follow-ups: Technical hiring panels frequently probe deeper into concurrency, backward compatibility, or alternative libraries.