Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
A manufacturing company collects sensor data from thousands of IoT devices. Each sensor reading includes a timestamp, device ID, and a variable set of measurements (e.g., temperature, pressure, vibration) that differ by device type. The company needs to store this data in a globally distributed NoSQL database that supports low-latency writes and flexible schema. Which Azure data store should they choose?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
Azure SQL Database
Azure SQL Database is a relational database that enforces a fixed schema. The varying sensor measurements would require schema changes or sparse columns, making it less suitable for flexible schemas.
B
Best answer
Azure Cosmos DB with the NoSQL API
Azure Cosmos DB NoSQL API stores JSON documents with a flexible schema, supports global distribution, and provides low-latency writes, making it ideal for IoT sensor data with variable attributes.
C
Distractor review
Azure Cache for Redis
Azure Cache for Redis is an in-memory data store primarily used for caching. While it offers low latency, it is not designed for durable storage of large volumes of sensor data with global distribution.
D
Distractor review
Azure Database for PostgreSQL
Azure Database for PostgreSQL is a relational database that requires a predefined schema. The variable measurements would need to be handled via JSON columns or separate tables, but it lacks native global distribution.
Common exam trap
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Technical deep dive
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
- Use explanations to understand the rule behind the answer.
TExam Day Tips
- Underline the problem statement mentally.
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Related practice questions
Related DP-900 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A data engineer needs to process streaming data from IoT devices and store the results in Azure Data Lake Storage for long-term analytics. The data must be processed in near real-time to detect anomalies and trigger alerts. Which Azure service should the engineer use for stream processing?
Question 2
A data engineer needs to query data stored in CSV files in Azure Data Lake Storage Gen2 using T-SQL in Azure Synapse Analytics, without loading the data into the database. Which feature should they use?
Question 3
A data engineer needs to process raw clickstream data from multiple websites that is stored in Azure Blob Storage as JSON files. The processing must run automatically every hour, transform the data into a structured format for reporting, and handle schema changes in the source data without manual intervention. Which Azure service should be used?
Question 4
A data engineer is designing a data lake architecture in Azure. They plan to first ingest raw data from various sources into a landing zone in Azure Data Lake Storage Gen2. Then they will clean, validate, and deduplicate that data in a second zone. Finally, they will create aggregated, business-ready datasets in a third zone for analysts. This layered approach is known as which architecture?
Question 5
A data engineer needs to transform large datasets stored in Azure Data Lake Storage Gen2 using Python and Apache Spark. They want a serverless compute option that automatically scales and requires no cluster management. Which Azure service should they use?
Question 6
A company collects customer feedback forms. Each form contains always-present fields like CustomerID and SubmissionDate, but also a free-text Comments field and optional fields like Rating or ProductCategory that vary between forms. How should this data be classified?
FAQ
Questions learners often ask
What does this DP-900 question test?
Read the scenario before looking for a memorised answer.
What is the correct answer to this question?
The correct answer is: Azure Cosmos DB with the NoSQL API — Azure Cosmos DB with the NoSQL API (Document API) is a globally distributed, multi-model database service that supports flexible schemas (JSON documents). It provides low-latency writes and reads, automatic indexing, and turnkey global distribution. This makes it the best choice for IoT sensor data with varying schemas. Azure SQL Database and Azure Database for PostgreSQL are relational databases that require a fixed schema. Azure Cache for Redis is an in-memory cache, not a durable NoSQL store for this scenario.
What should I do if I get this DP-900 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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