You want to prevent deadlocks in a system where multiple transactions update two tables, Orders and Customers. Which approach is best?

hard📝 Application Q15 of 15

SQL - Transactions and Data Integrity

You want to prevent deadlocks in a system where multiple transactions update two tables, Orders and Customers. Which approach is best?

AEnsure all transactions update <code>Customers</code> first, then <code>Orders</code>, and keep transactions short

BAllow transactions to update tables in any order but increase isolation level to SERIALIZABLE

CUse long transactions with many updates to reduce lock frequency

DDisable locking to speed up updates

Step-by-Step Solution

Solution:

Step 1: Understand deadlock prevention principles
Accessing resources in the same order and keeping transactions short reduces deadlocks.
Step 2: Evaluate options for best practice
Ensure all transactions update Customers first, then Orders, and keep transactions short enforces consistent order and short transactions, preventing deadlocks effectively.
Step 3: Analyze other options
Allow transactions to update tables in any order but increase isolation level to SERIALIZABLE may increase deadlocks; Use long transactions with many updates to reduce lock frequency lengthens locks; Disable locking to speed up updates is unsafe and invalid.
Final Answer:
Ensure all transactions update Customers first, then Orders, and keep transactions short -> Option A
Quick Check:
Consistent order + short transactions = Deadlock prevention [OK]

Quick Trick: Use same update order and short transactions to prevent deadlocks [OK]

Common Mistakes:

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