Quick Answer
Azure Cosmos DB is the correct choice because it is the only Azure service that combines globally distributed, multi-region writes with guaranteed ACID transactions via its transactional batch API, while delivering single-digit millisecond latency for point lookups by a unique key. This unique capability stems from its multi-model design and automatic indexing, which allow it to maintain strong consistency across continents without sacrificing speed. On the Microsoft Azure Data Fundamentals DP-900 exam, this question tests your understanding of when to choose a globally distributed NoSQL database over a relational one like Azure SQL Database, which cannot natively span regions with low latency. A common trap is assuming Azure SQL Database supports global ACID transactions, but it lacks native multi-region write support and cannot match Cosmos DB’s sub-10-millisecond reads. Remember the memory tip: “Cosmos for global, ACID, and low-latency clicks” — if your app needs all three, Cosmos DB is the fix.
This DP-900 practice question tests your understanding of describe core data concepts. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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.
You need to design a data storage solution for a global e-commerce application that must support ACID transactions and require minimal latency for point lookups by a unique key. Which Azure data service should you use?
Azure Table Storage
Why wrong: Azure Table Storage does not support ACID transactions.
Azure SQL Database
Why wrong: Azure SQL supports ACID but may have higher latency for global access.
Azure Blob Storage
Why wrong: Blob Storage is for unstructured data, not transactional point lookups.
Azure Cosmos DB
Cosmos DB provides low-latency point lookups and ACID transactions within a logical partition.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Azure Cosmos DB
Azure Cosmos DB is the correct choice because it provides global distribution with multi-region writes, guarantees ACID transactions through its transactional batch API, and offers single-digit millisecond latency for point reads by a unique key (e.g., id and partition key). This makes it ideal for a global e-commerce application requiring both strong consistency and low-latency lookups.
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.
Azure Table Storage
Why it's wrong here
Azure Table Storage does not support ACID transactions.
Azure SQL Database
Why it's wrong here
Azure SQL supports ACID but may have higher latency for global access.
Azure Blob Storage
Why it's wrong here
Blob Storage is for unstructured data, not transactional point lookups.
Azure Cosmos DB
Why this is correct
Cosmos DB provides low-latency point lookups and ACID transactions within a logical partition.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
The trap here is that candidates often assume Azure SQL Database is the only ACID-compliant option, overlooking Cosmos DB's transactional batch support and its superior global low-latency capabilities.
Detailed technical explanation
Under the hood, Cosmos DB uses a hash-based partitioning scheme where each logical partition is replicated across multiple regions; point reads by partition key and item ID are served directly from the local replica, bypassing cross-region coordination. The transactional batch API leverages a single-partition transaction scope, ensuring all operations within the batch either commit or roll back atomically. In a real-world scenario, a global e-commerce cart service can use Cosmos DB to update inventory and order status in one transaction while maintaining sub-10 ms reads from any region.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Describe core data concepts — study guide chapter
Learn the concepts, then practise the questions
Describe core data concepts practice questions
Targeted practice on this topic area only
All DP-900 questions
982 questions across all exam domains
Microsoft Azure Data Fundamentals DP-900 study guide
Full concept coverage aligned to exam objectives
DP-900 practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Practise DP-900 questions linked to Describe core data concepts.
Practise DP-900 questions linked to Describe an analytics workload on Azure.
Practise DP-900 questions linked to Identify considerations for relational data on Azure.
Practise DP-900 questions linked to Describe considerations for working with non-relational data on Azure.
Practise DP-900 questions linked to DP-900 fundamentals.
Practise DP-900 questions linked to DP-900 scenario.
Practise DP-900 questions linked to DP-900 troubleshooting.
Practice this exam
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Describe core data concepts — This question tests Describe core data concepts — Read the scenario before looking for a memorised answer..
The correct answer is: Azure Cosmos DB — Azure Cosmos DB is the correct choice because it provides global distribution with multi-region writes, guarantees ACID transactions through its transactional batch API, and offers single-digit millisecond latency for point reads by a unique key (e.g., id and partition key). This makes it ideal for a global e-commerce application requiring both strong consistency and low-latency lookups.
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.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Keep practising
Last reviewed: Jun 24, 2026
This DP-900 practice question is part of Courseiva's free Microsoft 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 DP-900 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.