DynamoDB vs Relational Databases — Which to Choose?
Which THREE factors should be considered when choosing between Amazon DynamoDB and Amazon Aurora for a new application? (Select THREE.)
Quick Answer
The answer is the scalability model, access pattern, and transaction support. These three factors are the primary differentiators because DynamoDB is built for horizontal scaling with key-value access patterns and limited transactional capabilities, while Amazon Aurora is a relational database designed for vertical scaling, complex SQL queries, and full ACID transactions. On the AWS Certified Database Specialty DBS-C01 exam, this comparison tests your ability to match workload requirements to the correct database service, often appearing in scenario-based questions where you must identify why a relational model fails for high-throughput, low-latency needs. A common trap is focusing on data size or cost, which are not decisive here—both services can handle large datasets and have similar pricing tiers. Instead, remember the mnemonic “SAT” for Scalability, Access pattern, and Transaction support to quickly eliminate wrong answers.
⚠ Common exam trap
Candidates often confuse cost per GB or table size limits as decisive factors, but the DBS-C01 exam emphasizes access patterns, query complexity, and scalability model as the core architectural considerations.
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
✓
Access patterns (key-value vs relational queries)
DynamoDB is optimized for key-value and document access patterns with single-digit millisecond latency at any scale, while Aurora is a relational database designed for SQL queries with joins and complex filtering. The choice between them hinges on whether the application requires simple key-based lookups (DynamoDB) or relational queries with multiple access patterns (Aurora).
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Access patterns (key-value vs relational queries)
Why this is correct
Determines NoSQL vs SQL choice.
- ✓
Need for complex joins and transactions
Why this is correct
Aurora supports ACID transactions with joins.
- ✓
Scalability model (horizontal vs vertical)
Why this is correct
DynamoDB scales horizontally; Aurora scales vertically.
- ✗
Cost per GB of storage
Why it's wrong here
Not a primary factor; both have different pricing.
- ✗
Maximum data size per table
Why it's wrong here
Both can handle large datasets.
Go deeper
Related to this question
About these practice questions
This DBS-C01 question is part of Courseiva's 1,663-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
Same concept, more angles
1 more way 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 THREE factors should be considered when choosing between Amazon RDS and Amazon DynamoDB for a new application? (Choose 3.)
medium- A.Cost of storage
- B.Need for encryption at rest
- ✓ C.Access patterns (predictable vs. ad-hoc)
- ✓ D.Scalability requirements (horizontal vs. vertical)
- ✓ E.Query complexity (joins, aggregations)
Why C: Amazon RDS is a relational database service that excels at complex queries involving joins and aggregations, while DynamoDB is a NoSQL key-value and document database optimized for predictable, high-scale access patterns. The choice between them hinges on whether the application requires relational features (RDS) or can tolerate denormalized schemas for low-latency, horizontal scaling (DynamoDB). Option C is correct because DynamoDB is designed for ad-hoc, single-key lookups and simple queries, whereas RDS supports complex, ad-hoc SQL queries with joins.
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.