In one sentence
Select the database by data model and access pattern: relational, key-value, document, or graph.
Key points
- RDS fits SQL, transactions, joins, and familiar relational engines.
- DynamoDB fits serverless key-value and document access built around partition keys.
- DocumentDB fits MongoDB-compatible document workloads with nested JSON-like data.
Exam takeaway
Neptune fits relationship-heavy graph traversal such as fraud networks, knowledge graphs, and social connections.