DP-900 Practice Question: Identify considerations for relational data on Azure
A startup is building a web application with a relational database backend. They expect variable traffic and want to minimize costs by scaling the database automatically based on demand. Which Azure service should they use?
⚠ Common exam trap
A common mix-up: candidates confuse 'serverless' with 'PaaS' broadly, assuming all Azure relational PaaS offerings (like Azure SQL Managed Instance or Azure Database for MariaDB) automatically scale, when in fact only Azure SQL Database serverless provides the specific auto-scaling and auto-pause features for cost optimization under variable traffic.
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 SQL Database serverless
Azure SQL Database serverless is the correct choice because it automatically scales compute resources based on demand and pauses the database during idle periods, charging only for storage and minimal compute. This aligns with the startup's need for variable traffic and cost minimization, as it eliminates the need to provision for peak capacity manually.
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 SQL Database serverless
Why this is correct
Azure SQL Database serverless provides automatic compute scaling that responds to workload demand, and it can pause the database entirely during idle periods. Billing is per-second based on actual compute usage, not provisioned capacity, making it cost-efficient for intermittent or unpredictable application traffic. The startup's web application with variable load fits this model perfectly.
- ✗
Azure SQL Managed Instance
Why it's wrong here
Azure SQL Managed Instance is a PaaS offering that closely mimics on-premises SQL Server, but it does not include a serverless compute tier. The compute resources (vCores) are provisioned and billed continuously, regardless of actual workload, so there is no auto-scale or auto-pause capability. For a variable workload, you would overpay during idle times.
- ✗
SQL Server on Azure Virtual Machines
Why it's wrong here
SQL Server on Azure Virtual Machines is an IaaS solution where you control the VM size and must manually resize to handle more or less demand. Scaling requires stopping the VM, changing its configuration, and restarting — there is no built-in auto-scaling or passive billing. It also demands patching and maintenance, making it poorly suited for a cost-sensitive startup needing dynamic scalability.
- ✗
Azure Database for MariaDB
Why it's wrong here
Azure Database for MariaDB is a fully managed PaaS database, but its compute tiers are fixed and do not offer a serverless compute option. While you can manually scale between predefined compute tiers, the service will never automatically pause or scale down during idle periods. Thus it lacks the cost-saving dynamic compute model that Azure SQL Database serverless provides.
Quick reference
Cloud Service Model Comparison
| Model | You Manage | Provider Manages | Examples |
|---|---|---|---|
| IaaS | OS, runtime, apps, data | Hardware, hypervisor, networking | EC2, Azure VMs, GCP Compute Engine |
| PaaS | Apps and data | OS, runtime, middleware, hardware | Elastic Beanstalk, Azure App Service |
| SaaS | Data and settings only | Everything else | Microsoft 365, Salesforce, Workday |
| FaaS / Serverless | Function code only | Infra, scaling, runtime | Lambda, Azure Functions, Cloud Run |
| CaaS | Containers and apps | Kubernetes, OS, hardware | EKS, AKS, GKE |
Go deeper
Related to this question
Learn chapter
Relational Data Concepts
Key term
Azure SQL Database
Azure SQL Database is a fully managed relational database-as-a-service (DBaaS) in Microsoft Azure, based on the SQL Server engine, that handles scaling, backups, patching, and high availability automatically.
Key term
Relational database
A relational database organizes data into tables with rows and columns, where each table relates to others using unique keys, allowing efficient storage, retrieval, and manipulation of structured information.
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Written by Johnson Ajibi, MSc IT Security
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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.