DP-900 Describe core data concepts Practice Question
A company stores IoT sensor data in Azure Blob Storage. Data scientists need to query the data using SQL without moving it to another store. Which Azure service should they use?
⚠ Common exam trap
Many exam-takers confuse Azure Data Lake Storage (a storage layer) with a query service, or assume Azure SQL Database can query external files directly, when in fact only Synapse Serverless SQL pool (or PolyBase in dedicated SQL pool) provides native SQL-on-file capabilities for Blob Storage.
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
✓
Azure Synapse Serverless SQL pool
Azure Synapse Serverless SQL pool allows you to query data directly from Azure Blob Storage using T-SQL without moving or copying the data. It uses a distributed query engine that reads files (Parquet, CSV, JSON) in place, making it ideal for ad-hoc analytics over IoT sensor data stored in Blob Storage.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Azure Synapse Serverless SQL pool
Why this is correct
Azure Synapse Serverless SQL pool is the correct choice because it is a serverless query engine that uses T-SQL to query IoT sensor data directly from Azure Blob Storage in place, without requiring any data movement or ingestion. It leverages OPENROWSET or external tables to read files such as CSV, JSON, or Parquet, and is ideal for ad-hoc or interactive analysis over raw data. You only pay for the amount of data processed, making it a cost-effective, on-demand option for exploring Blob Storage data.
- ✗
Azure Analysis Services
Why it's wrong here
Azure Analysis Services is not suitable here because it is a semantic modeling and OLAP engine that compresses and caches data into an in-memory tabular model for high-performance, interactive business intelligence analytics. It does not provide native SQL query capabilities over raw files in Blob Storage; rather, you would need to first import data from various sources into its model. This adds an ETL step and is designed for curated, aggregated analytics rather than directly querying IoT sensor blobs with SQL.
- ✗
Azure Data Lake Storage
Why it's wrong here
Azure Data Lake Storage is a storage service, not a query engine, so it cannot execute SQL queries of any kind. It is a highly scalable, secure, and hierarchical namespace-based storage layer built on Blob Storage, commonly used to store large volumes of raw IoT data. While you can store the sensor data there, you would still need a separate compute engine such as Azure Synapse Serverless SQL, Azure Databricks, or Azure HDInsight to actually query and analyze the data.
- ✗
Azure SQL Database
Why it's wrong here
Azure SQL Database is a managed relational database engine that requires data to be loaded into structured tables before it can be queried. It does not support querying arbitrary files sitting in Azure Blob Storage directly; you would need to copy the sensor data into SQL Database tables, which involves data movement and additional complexity. This is contrary to the goal of querying the IoT data in place in Blob Storage, and it would incur storage and ingestion costs beyond the original blob storage.
Quick reference
Azure Blob Storage Tier Comparison
| Tier | Storage Cost | Retrieval Cost | Latency | Use Case |
|---|---|---|---|---|
| Hot | Highest | Lowest | Immediate | Active data, frequent reads |
| Cool | Lower | Higher | Immediate | Data accessed < once / month |
| Cold | Lower still | Higher | Immediate | Data accessed < once / quarter |
| Archive | Lowest | Highest + rehydration delay | Hours | Long-term compliance retention |
Go deeper
Related to this question
Learn chapter
Data Roles and Core Concepts
Key term
Serverless SQL pool
Serverless SQL pool is an on-demand, pay-per-query analytics service in Azure that lets you query data stored in data lakes without provisioning or managing any dedicated infrastructure.
Key term
Service
A service is a software component or system that performs a specific function and is available to be used by other programs or users over a network.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.