Question 1easymultiple choice
Full question →easymultiple choiceObjective-mapped
A mobile game developer needs to store player session data. Each session has a unique SessionID, a UserID, a start timestamp, an end timestamp, and a collection of game events (each event is a JSON object). The application requires low-latency point reads by SessionID and the ability to query all sessions for a given UserID within a time range. The schema of game events can vary between sessions (e.g., new event types added frequently). The developer wants a fully managed NoSQL database that supports flexible schemas and secondary indexing. 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
Best answer
Azure Cosmos DB with the NoSQL API
Cosmos DB provides document storage with flexible schema, indexing, and low-latency reads. It supports secondary indexes on arbitrary fields like UserID and timestamp.
B
Distractor review
Azure Table Storage
Table Storage is a key-value store and does not natively support JSON documents or secondary indexing. Querying by UserID would require a table scan unless UserID is the partition key.
C
Distractor review
Azure Blob Storage
Blob storage is for large binary or text files. It does not support querying at the record level or indexing. Retrieving individual sessions would require scanning all blobs.
D
Distractor review
Azure Cache for Redis
Redis is an in-memory cache, not a durable data store. It does not support complex queries or secondary indexing natively.
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 — The requirements include flexible schema (JSON documents), low-latency point reads by SessionID, and querying by UserID and time range. Azure Cosmos DB with the NoSQL API supports document storage, flexible schemas, and secondary indexing. Azure Table Storage is a key-value store with limited querying (no secondary indexing). Azure Blob Storage is for unstructured blobs, not suitable for querying individual sessions. Azure Cache for Redis is an in-memory cache, not a durable primary store. Therefore, Cosmos DB is the best choice.
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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