Quick Answer
The answer is atomicity, because the banking transfer is left partially completed after the power failure, violating the requirement that a transaction be treated as a single, indivisible unit of work. Atomicity ensures that either all steps of a transaction succeed or none are applied; here, the savings deduction was committed but the checking credit was not, leaving the database in an inconsistent state. This is a classic ACID atomicity violation example that tests your understanding of transaction indivisibility on the CompTIA ITF+ FC0-U61 exam, where scenario-based questions often present a partial update to see if you can identify the broken property. A common trap is confusing atomicity with durability, but remember: atomicity is about all-or-nothing execution, while durability concerns permanent storage after commit. For a quick memory tip, think of atomicity as “A for All-or-Nothing” — if a transaction stops mid-step, atomicity demands a rollback to the starting point.
This FC0-U61 practice question tests your understanding of database fundamentals. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A banking transaction transfers money from savings to checking. The system updates the savings balance, then the power fails before the checking balance is updated. Which ACID property is violated?
Atomicity
Atomicity requires all or nothing; partial update violates it.
Isolation
Why wrong: Isolation deals with concurrent transactions.
Durability
Why wrong: Durability concerns committed data surviving failures.
Consistency
Why wrong: Consistency ensures data validity, but the partial update is an atomicity failure.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Atomicity
Atomicity ensures that a transaction is treated as a single, indivisible unit of work. In this scenario, the transfer operation consists of two steps: deducting from savings and crediting to checking. Because the power failure occurs after the savings balance is updated but before the checking balance is updated, the transaction is left partially completed, violating atomicity. The system must either complete both steps or roll back the first step to maintain atomicity.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Atomicity
Why this is correct
Atomicity requires all or nothing; partial update violates it.
Related concept
Read the scenario before looking for a memorised answer.
Isolation
Why it's wrong here
Isolation deals with concurrent transactions.
Durability
Why it's wrong here
Durability concerns committed data surviving failures.
Consistency
Why it's wrong here
Consistency ensures data validity, but the partial update is an atomicity failure.
Common exam traps
The trap here is that candidates often confuse atomicity with consistency, thinking a partial update violates consistency first, but the core issue is that the transaction did not complete as an atomic unit, which is the direct violation of atomicity.
Detailed technical explanation
Under the hood, database systems implement atomicity using a write-ahead log (WAL) or undo/redo logs. In a banking system, the transaction would begin with a BEGIN TRANSACTION statement, and upon failure, the database recovery manager would use the log to roll back the savings debit, restoring the original balance. Real-world scenarios like ATM withdrawals or stock trades rely on atomicity to prevent lost funds or double-spending when network or power failures occur.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A practitioner preparing for the FC0-U61 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
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FAQ
Database Fundamentals — This question tests Database Fundamentals — Read the scenario before looking for a memorised answer..
The correct answer is: Atomicity — Atomicity ensures that a transaction is treated as a single, indivisible unit of work. In this scenario, the transfer operation consists of two steps: deducting from savings and crediting to checking. Because the power failure occurs after the savings balance is updated but before the checking balance is updated, the transaction is left partially completed, violating atomicity. The system must either complete both steps or roll back the first step to maintain atomicity.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 25, 2026
This FC0-U61 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the FC0-U61 exam.
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