Quick Answer
The answer is Azure Table Storage. This service is the most cost-effective choice because it is a NoSQL key-value store designed for semi-structured IoT data like temperature readings and device status, allowing efficient queries by partition key (device ID) and row key (timestamp) without requiring a fixed schema. On the Microsoft Azure Data Fundamentals DP-900 exam, this question tests your ability to match data workloads to the right Azure service, often contrasting Table Storage’s low cost and schema flexibility against more expensive options like Cosmos DB or SQL Database. A common trap is choosing Cosmos DB for its NoSQL capabilities, but remember that Table Storage is the budget-friendly alternative for simple time-series data. To lock it in, think of the mnemonic “T for Table, T for Time-series, T for Thrifty.”
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.
A company needs to store semi-structured data from IoT devices, including temperature readings and device status. The data will be queried by time range and device ID. Which Azure data service is most cost-effective for this use case?
Azure Blob Storage
Why wrong: Blob Storage is for unstructured binary data, not queryable by device ID.
Azure Cosmos DB
Why wrong: Cosmos DB is more expensive and offers more features than needed.
Azure SQL Database
Why wrong: SQL Database is a relational database and not cost-optimal for simple key-value data.
Azure Table Storage
Table Storage is a low-cost NoSQL store ideal for IoT telemetry.
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 Table Storage
Azure Table Storage is a NoSQL key-value store that is optimized for storing large amounts of semi-structured data without requiring a fixed schema. It supports efficient queries by partition key (device ID) and row key (timestamp), making it ideal for time-series IoT data at a lower cost than other Azure data services.
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 Blob Storage
Why it's wrong here
Blob Storage is for unstructured binary data, not queryable by device ID.
Azure Cosmos DB
Why it's wrong here
Cosmos DB is more expensive and offers more features than needed.
Azure SQL Database
Why it's wrong here
SQL Database is a relational database and not cost-optimal for simple key-value data.
Azure Table Storage
Why this is correct
Table Storage is a low-cost NoSQL store ideal for IoT telemetry.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
The trap here is that candidates often choose Azure Cosmos DB for its NoSQL capabilities, overlooking the fact that Table Storage provides the same key-value functionality at a fraction of the cost for simple IoT workloads.
Detailed technical explanation
Azure Table Storage uses a partition key (device ID) and row key (timestamp) to enable fast point queries and range scans via the OData protocol. Under the hood, it stores data in a flat namespace of tables, with each entity limited to 1 MB and a maximum of 255 properties, making it suitable for high-volume telemetry where each reading is a small record. In real-world IoT scenarios, you can combine Table Storage with Azure Stream Analytics for real-time ingestion and then query historical data directly using the Table REST API or SDKs.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
What to study next
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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 Table Storage — Azure Table Storage is a NoSQL key-value store that is optimized for storing large amounts of semi-structured data without requiring a fixed schema. It supports efficient queries by partition key (device ID) and row key (timestamp), making it ideal for time-series IoT data at a lower cost than other Azure data services.
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 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.
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