What is a Transaction and what are its ACID properties?
This question defines database transactions and the four pillars of reliability. It tests knowledge of data consistency.
Why Interviewers Ask This
Transactions ensure reliable processing of financial or critical data. Interviewers ask this to verify your understanding of atomicity and consistency. It is crucial for preventing partial updates that could corrupt data.
How to Answer This Question
Define a transaction as a unit of work. Explain ACID: Atomicity, Consistency, Isolation, Durability. Give examples for each property. Discuss commit and rollback mechanisms.
Key Points to Cover
- Unit of work definition
- Atomicity and Consistency
- Isolation levels
- Durability guarantee
Sample Answer
A transaction is a sequence of operations performed as a single logical unit of work. ACID stands for Atomicity (all or nothing), Consistency (valid state), Isolation (independent execution), and Durability (permanent st…
Common Mistakes to Avoid
- Mixing up ACID letters
- Ignoring isolation levels
- Not explaining rollback
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