DA0-002 Data Concepts and Environments Practice Question
A company uses an OLTP system for processing customer transactions. Which characteristic is most important for this system to ensure that each transaction is processed reliably, even if multiple users access the system simultaneously?
⚠ Common exam trap
Candidates often confuse OLTP with OLAP characteristics: candidates might pick columnar storage or complex analytical queries because they associate databases with analytics, but the question specifically asks for reliability under concurrent access, which points to ACID properties.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
It follows ACID properties
ACID properties (Atomicity, Consistency, Isolation, Durability) are the foundational guarantees that ensure each transaction in an OLTP system is processed reliably, even when multiple users access the system concurrently. Atomicity ensures all-or-nothing execution, Consistency preserves database invariants, Isolation prevents concurrent transactions from interfering with each other, and Durability guarantees committed transactions survive failures. These properties directly address the requirement for reliable transaction processing under simultaneous access.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
It uses a columnar storage format
Why it's wrong here
Columnar storage suits analytical workloads by reading few columns across many rows, not concurrent transaction processing. It is tempting because columnar databases are fast for reporting, but OLTP reliability under simultaneous users depends on ACID transactions and row-level locking, which columnar formats do not prioritise.
- ✗
It stores data in a denormalized schema
Why it's wrong here
Denormalised schemas suit read-heavy analytical or reporting systems, not transactional integrity. It is tempting because denormalisation speeds up reads, but OLTP reliability under concurrent access requires normalised structures with ACID transactions and locking to prevent anomalies, which denormalisation undermines.
- ✗
It supports complex analytical queries
Why it's wrong here
Complex analytical queries belong to OLAP or data warehouse workloads, not OLTP transaction processing. It is tempting because analytics adds business value, but the scenario demands reliable concurrent transaction handling, which relies on ACID properties and locking rather than query complexity.
- ✓
It follows ACID properties
Why this is correct
ACID properties guarantee atomicity, consistency, isolation and durability, so concurrent OLTP transactions commit reliably without partial writes or interference. Isolation specifically handles simultaneous users, while durability ensures committed transactions survive failure, matching the stem's reliability requirement.
About these practice questions
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official CompTIA exam blueprint
This DA0-002 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 DA0-002 exam.