Microsoft Azure Data Fundamentals — Question 299

A bank has a system that manages financial transactions.
When transferring money between accounts. the system must never retrieve a value for the source account that reflects the balance before the transfer and a value for the destination account that reflects the balance after the transfer.
Of which ACID semantic is this an example?

Answer options

• A. atomicity
• B. durability
• C. consistency
• D. isolation

Correct answer: D

Explanation

This example demonstrates the concept of isolation, which ensures that transactions are securely processed without interference, maintaining the integrity of concurrent transactions. Atomicity refers to the all-or-nothing nature of transactions, durability ensures that completed transactions persist, and consistency guarantees that a transaction will bring the database from one valid state to another, but these do not directly address the issue of balance visibility during transfers.