DEA-C01 Data Store Management Practice Question
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?
⚠ Common exam trap
Candidates often confuse Amazon S3's ability to store JSON documents with the need for low-latency primary key lookups, overlooking that S3 is not a database and lacks the indexing and query performance required for frequent, transactional reads and writes.
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 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.
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, massively parallel analytics warehouse tuned for large scans and aggregations, not flexible-schema document storage or single-digit-millisecond primary key lookups. It would be the right choice for complex analytical queries over structured, petabyte-scale datasets, not this workload.
- ✗
Amazon S3
Why it's wrong here
S3 is object storage with higher latency for individual item lookups via API calls.
- ✓
Amazon DynamoDB
Why this is correct
Amazon DynamoDB stores JSON as native documents and delivers single-digit-millisecond latency on primary key lookups, satisfying the low-latency requirement. Its schemaless key-value design accommodates the flexible schema, while provisioned throughput sustains the frequent reads and writes the web application generates.
- ✗
Amazon RDS for MySQL
Why it's wrong here
RDS for MySQL stores data in fixed relational schemas, so flexible-schema JSON documents need either schema migrations or JSON columns that lose indexing efficiency. It fits transactional relational workloads with joins and constraints, not document-oriented primary key access patterns.
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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.