SQL - Transactions and Data Integrity
Find the mistake in this SQL transaction to avoid deadlocks:
BEGIN TRANSACTION;
LOCK Table B;
LOCK Table A;
COMMIT;
BEGIN TRANSACTION;
LOCK Table B;
LOCK Table A;
COMMIT;
Find the mistake in this SQL transaction to avoid deadlocks:
medium📝 Debug Q7 of 15
Step-by-Step Solution
Solution:
Step 1: Analyze lock order
Locking Table B before Table A may conflict with other transactions locking in opposite order.Step 2: Identify deadlock risk
Inconsistent lock order can cause circular waits and deadlocks.Final Answer:
Locking tables in inconsistent order can cause deadlocks -> Option BQuick Check:
Inconsistent lock order = Deadlock risk [OK]
Quick Trick: Lock tables in consistent order to avoid deadlocks [OK]
Common Mistakes:
- Thinking ROLLBACK is mandatory every time
- Believing COMMIT must come before locks
- Ignoring lock order importance
Master "Transactions and Data Integrity" in SQL
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