DBS-C01 Management and Operations Practice Question
Which THREE factors should be considered when choosing between Amazon DynamoDB and Amazon RDS for a new application? (Choose three.)
⚠ Common exam trap
A common mix-up: candidates assume automatic failover across multiple Regions is unique to one service, but both DynamoDB (global tables) and RDS (cross-Region read replicas with manual promotion) can achieve this, making it a non-differentiating factor.
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
✓
Need for ACID transactions across multiple rows
Amazon RDS supports ACID transactions across multiple rows using traditional SQL databases like MySQL or PostgreSQL, which is essential for applications requiring strict consistency (e.g., financial systems). Amazon DynamoDB, while supporting ACID transactions via the TransactGetItems and TransactWriteItems APIs, is optimized for single-item or limited multi-item operations and may not perform as well for complex multi-row transactional workloads. The need for ACID across multiple rows is a key differentiator favoring RDS.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Need for ACID transactions across multiple rows
Why this is correct
RDS supports full ACID; DynamoDB supports transactional APIs but limited.
- ✓
Need for complex join queries across multiple tables
Why this is correct
RDS supports joins; DynamoDB does not.
- ✗
Need for automatic failover in multiple AWS Regions
Why it's wrong here
Both can be configured for multi-region.
- ✓
Requirement for flexible schema with document data
Why this is correct
DynamoDB is schema-less; RDS requires defined schema.
- ✗
Data size exceeding 10 TB
Why it's wrong here
Both can handle large data sizes.
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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.