AZ-204 Develop for Azure storage Practice Question
A serverless app must react whenever audit documents are inserted or updated in Cosmos DB. Which trigger should the Azure Function use? The design must avoid adding custom operational scripts.
⚠ Common exam trap
Many exam-takers confuse the Cosmos DB trigger with other triggers that require custom polling or external invocation, overlooking that the change feed provides a built-in, event-driven mechanism for reacting to data changes.
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
✓
Cosmos DB trigger
The Azure Cosmos DB trigger is the correct choice because it natively listens to the Cosmos DB change feed, which captures inserts and updates to documents. This allows the Azure Function to react automatically without any custom scripts or polling logic, aligning with the serverless and operational simplicity requirements.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Queue trigger
Why it's wrong here
Queue triggers respond to queue messages, not Cosmos DB changes directly.
- ✗
Timer trigger
Why it's wrong here
A timer trigger runs on a schedule and does not automatically follow the change feed.
- ✗
HTTP trigger
Why it's wrong here
HTTP triggers require incoming HTTP requests.
- ✓
Cosmos DB trigger
Why this is correct
The Cosmos DB trigger reads the change feed and invokes the function for inserts and updates.
Visual reference
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 |
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This AZ-204 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 AZ-204 exam.