iFinancial databases that support card authorizations, statement balances, and ledger updates must preserve correctness even when many writes happen at once. In a payments environment, small consistency failures can become customer-facing balance errors or compliance issues.
You are asked to explain the four ACID properties in database management systems—Atomicity, Consistency, Isolation, and Durability—and why they are especially important for financial transaction databases such as those behind American Express card activity and account ledgers.
Keep your answer at an interview-ready level: define each property clearly, describe what can go wrong if it is missing, and connect the concept to practical transaction examples like debits, credits, reversals, duplicate charges, and concurrent balance updates. You do not need to discuss database internals in depth, but you should show that you understand both the theory and the operational impact.
