DEA-C01 Data Store Management Practice Question
A data engineer needs to store JSON documents that are frequently accessed by a low-latency web application. The data does not require complex queries, and the access pattern is primarily by a key. Which AWS service is most appropriate?
⚠ Common exam trap
It's easy for candidates to confuse ElastiCache for Redis as a persistent data store for JSON documents, but it is primarily an in-memory cache with optional persistence, not a durable, low-latency database designed for primary key access patterns.
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
✓
Amazon DynamoDB
Amazon DynamoDB is the most appropriate service because it is a fully managed NoSQL key-value and document database designed for single-digit millisecond latency at any scale. It natively supports JSON documents and provides fast, consistent access by primary key without requiring complex query capabilities, making it ideal for low-latency web applications.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Amazon ElastiCache for Redis
Why it's wrong here
ElastiCache for Redis is an in-memory cache, not durable primary storage, so data would not persist reliably as the system of record. It is tempting because it delivers the required low latency, and it would be correct as a caching layer in front of a durable store.
- ✗
Amazon S3
Why it's wrong here
S3 has higher latency for frequent reads compared to DynamoDB.
- ✗
Amazon RDS for MySQL
Why it's wrong here
RDS for MySQL stores JSON in a relational schema, adding query and connection overhead that a key-based document lookup does not need. It is tempting because RDS is a familiar managed database, and it would suit relational or complex-query workloads rather than low-latency key access.
- ✓
Amazon DynamoDB
Why this is correct
Amazon DynamoDB stores JSON as native items and retrieves them by primary key in single-digit milliseconds, satisfying the low-latency, key-based access pattern. Its schemaless design handles document data without complex query requirements, unlike relational engines or object storage, which add overhead unnecessary for this workload.
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Same concept, more angles
1 more way this is tested on DEA-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. A data engineer needs to store JSON documents that are frequently read and written by a web application. The data has a flexible schema and requires low-latency queries on primary key lookups. Which AWS service is MOST suitable?
easy- A.Amazon Redshift
- B.Amazon S3
- ✓ C.Amazon DynamoDB
- D.Amazon RDS for MySQL
Why C: Amazon DynamoDB is the most suitable service because it is a NoSQL key-value and document database that provides single-digit millisecond latency for primary key lookups, supports flexible schemas for JSON documents, and is designed for high-throughput read/write workloads from web applications. Its fully managed nature and auto-scaling capabilities align with the requirement for frequent, low-latency queries on a flexible schema.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DEA-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 DEA-C01 exam.