DEA-C01 Data Store Management Practice Question
A company needs to store JSON documents that are accessed by a key-value pattern. The data is 500 GB and requires single-digit millisecond latency. Which AWS database is most suitable?
⚠ Common exam trap
A common mix-up: candidates choose Amazon RDS for MySQL because they associate JSON documents with relational databases, overlooking that DynamoDB is purpose-built for key-value and document workloads with guaranteed single-digit millisecond latency, while RDS introduces schema rigidity and higher latency for this pattern.
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 suitable choice because it is a fully managed NoSQL key-value and document database that delivers single-digit millisecond latency at any scale, making it ideal for storing and retrieving JSON documents via a key-value access pattern. It supports document data types natively and can handle 500 GB of data efficiently with consistent low-latency performance.
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 Redshift
Why it's wrong here
Redshift is a columnar data warehouse built for analytical SQL queries over large datasets, not key-value retrieval, so it cannot meet single-digit millisecond latency for document lookups. It is tempting because Redshift handles 500 GB volumes comfortably, and would be correct if the workload were aggregate reporting rather than key-based document access.
- ✓
Amazon DynamoDB
Why this is correct
DynamoDB is a fully managed key-value and document store delivering consistent single-digit millisecond latency at any scale, comfortably handling 500 GB of JSON documents accessed by primary key. Relational or object stores cannot meet that latency and access pattern.
- ✗
Amazon Neptune
Why it's wrong here
Neptune is a graph database optimised for traversing relationships between nodes and edges, not key-value lookups, so it cannot deliver single-digit millisecond latency for this access pattern. It is tempting because Neptune does store JSON-like property graph data, and would be correct if the workload required querying connected entities rather than retrieving documents by key.
- ✗
Amazon RDS for MySQL
Why it's wrong here
Amazon RDS for MySQL is a relational engine, so JSON documents are queried through SQL rather than native key-value lookups, and single-digit millisecond latency at 500 GB is not guaranteed. It is tempting because RDS is familiar and supports JSON columns, which suits modest relational workloads.
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Same concept, more angles
2 more ways 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 accessed by a serverless application using AWS Lambda. The documents are frequently updated and need low latency (single-digit milliseconds) for read and write operations. Which AWS service should the engineer use?
easy- ✓ A.Amazon DynamoDB
- B.Amazon ElastiCache for Redis
- C.Amazon S3 (with S3 Select)
- D.Amazon RDS for MySQL
Why A: Amazon DynamoDB is a fully managed NoSQL key-value and document database that provides single-digit millisecond latency for read and write operations at any scale. It natively supports JSON documents, integrates directly with AWS Lambda via the AWS SDK, and handles frequent updates efficiently through its auto-scaling and on-demand capacity modes, making it ideal for serverless applications requiring low-latency data access.
Variation 2. A data engineer needs to store JSON documents that are accessed by a key-value pattern. The workload requires single-digit millisecond latency at any scale. Which AWS service is most appropriate?
medium- A.Amazon DocumentDB (with MongoDB compatibility)
- B.Amazon RDS for PostgreSQL
- ✓ C.Amazon DynamoDB
- D.Amazon Neptune
Why C: Amazon DynamoDB is a fully managed NoSQL key-value and document database that delivers single-digit millisecond latency at any scale. It is optimized for key-value access patterns, making it the ideal choice for storing and retrieving JSON documents by a primary key with consistent low latency.
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.