DP-900 Describe core data concepts Practice Question
Your company stores IoT sensor data in Azure Blob Storage. Data analysts need to query the data using SQL without moving it. Which Azure service should you use?
⚠ Common exam trap
It's easy for candidates to confuse Azure Synapse Serverless SQL with Azure SQL Database, mistakenly thinking any 'SQL' service can query external storage, but Azure SQL Database requires data to be loaded into its own tables, while Serverless SQL queries data in place.
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
Azure Synapse Serverless SQL is the correct choice because it provides a SQL-based query engine that can directly query data stored in Azure Blob Storage using T-SQL, without requiring data movement or a dedicated data warehouse. It uses a pay-per-query model and supports reading various file formats like Parquet, CSV, and JSON, making it ideal for ad-hoc analytical queries on IoT sensor data.
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 Stream Analytics
Why it's wrong here
Azure Stream Analytics is purpose-built for real-time event processing, consuming data from sources like IoT Hub, Event Hubs, or Blob storage input paths, and applying in-memory/streaming SQL logic over time windows. It is not designed for interactive, ad-hoc T-SQL queries over historical files already sitting in Blob Storage; instead, it continuously outputs results to sinks, making it a wrong answer for a serverless query-over-stored-data requirement.
- ✗
Azure Data Lake Storage
Why it's wrong here
Azure Data Lake Storage (ADLS) Gen2 is a scalable, hierarchical-namespace-enabled storage service built on Azure Blob Storage; it is the location where data lives, not a query engine. Although you can point analytics services at ADLS, the service itself does not expose a T-SQL endpoint or execute queries, so using it alone would not satisfy the need to query the IoT sensor data in the existing Blob Storage container.
- ✓
Azure Synapse Serverless SQL
Why this is correct
Azure Synapse Serverless SQL is the correct service because it provides a distributed T-SQL query engine that reads files directly from Azure Blob Storage or ADLS Gen2 using OPENROWSET or external tables, without requiring any data movement or loading. It can issue ad-hoc queries over Parquet, CSV, and JSON files, and it charges based on the amount of data processed, making it ideal for exploring stored IoT sensor data with SQL compatibility.
- ✗
Azure SQL Database
Why it's wrong here
Azure SQL Database is a fully managed relational database engine that requires data to be imported, inserted, or loaded into database tables via tools like BULK INSERT, Data Factory, or external table ELT pipelines before you can query it. While you can use T-SQL to read data inside the database, it cannot directly query raw files in Blob Storage; thus, it is unsuitable here because the requirement is to query the existing blob-stored sensor data in place, not to move it.
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
Data warehouse
A data warehouse is a central repository that stores large amounts of structured data from multiple sources, optimized for querying and analysis rather than day-to-day transactions.
Key term
Blob storage
Blob storage is a cloud service for storing large amounts of unstructured data, such as text or binary data, like documents, images, and videos.
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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.