DBS-C01 Workload-Specific Database Design Practice Question
Which THREE are factors to consider when choosing between Amazon RDS and Amazon DynamoDB? (Select THREE.)
⚠ Common exam trap
Candidates often think encryption at rest or in-memory caching are exclusive to one service, but AWS offers these features across both RDS and DynamoDB, making them irrelevant for choosing between the two.
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
✓
Serverless capacity management
Amazon RDS requires manual or auto-scaling of compute and storage capacity, while DynamoDB offers serverless capacity management with on-demand mode that automatically scales throughput based on traffic. This is a key differentiator when deciding between provisioned capacity (RDS) and fully managed, pay-per-request scaling (DynamoDB).
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Serverless capacity management
Why this is correct
DynamoDB is serverless; RDS requires provisioning.
- ✓
ACID transaction support across multiple tables
Why this is correct
RDS supports ACID across tables; DynamoDB supports only single-table transactions.
- ✓
Need for complex joins and relationships
Why this is correct
RDS supports joins; DynamoDB does not.
- ✗
Encryption at rest requirements
Why it's wrong here
Both support encryption at rest.
- ✗
Need for in-memory caching
Why it's wrong here
Neither is an in-memory cache; both can be used with ElastiCache.
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
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Same concept, more angles
2 more ways this is tested on DBS-C01
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Which TWO factors should you consider when choosing between Amazon RDS and Amazon DynamoDB for a new application?
medium- ✓ A.RDS requires a predefined schema, while DynamoDB is schema-less.
- B.DynamoDB can only be accessed from within a VPC, while RDS can be public.
- C.Only RDS supports Multi-AZ deployments for high availability.
- D.Both services support encryption at rest and in transit.
- ✓ E.DynamoDB is better suited for unstructured data, while RDS is better for structured data with complex relationships.
Why A: Amazon RDS (relational database service) requires a predefined schema with tables, columns, and data types before data can be inserted, enforcing ACID compliance and referential integrity. In contrast, Amazon DynamoDB is a NoSQL key-value and document database that is schema-less, allowing you to store items with varying attributes without upfront schema definition, which is ideal for agile development and unstructured data.
Variation 2. Which TWO factors should be considered when choosing between Amazon DynamoDB and Amazon RDS for MySQL for a new e-commerce application with variable traffic patterns?
medium- A.Ability to perform complex joins and aggregations: DynamoDB supports SQL-like queries.
- ✓ B.Operational overhead: DynamoDB is serverless, RDS requires patching and provisioning.
- C.Support for ACID transactions in both databases.
- D.Encryption at rest is only available for RDS.
- ✓ E.Automatic scaling of throughput with DynamoDB on-demand vs. manual scaling of RDS.
Why B: DynamoDB is a fully managed serverless service that eliminates the need for patching, provisioning, or managing servers, whereas Amazon RDS for MySQL requires manual patching, scaling, and instance provisioning. This operational overhead difference is critical for variable traffic patterns, as DynamoDB automatically handles infrastructure management, reducing administrative burden.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DBS-C01 practice question is part of Courseiva's free Amazon Web Services 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 DBS-C01 exam.