DynamoDB is AWS’s fully managed NoSQL database, and the exam tests two things: what that means, and when to reach for it instead of a relational database. Neither needs hands-on modelling — just the ability to match a data shape to the right service.
What it is
Amazon DynamoDB stores data in a key-value and document model — you fetch items by key rather than joining relational tables. It is fully managed: AWS runs the servers, scaling, patching and replication, so there is nothing to provision. And it delivers consistent single-digit-millisecond performance at any scale, which is its headline promise. When a question stresses NoSQL, key-value, and fast at scale, it is describing DynamoDB.
Capacity: on-demand vs provisioned
DynamoDB has two capacity modes, and the exam may ask which fits:
- On-demand — pay per request, scales automatically, no capacity planning. Best for unpredictable or variable traffic.
- Provisioned — you set the capacity, which can be cheaper for steady, predictable workloads.
Unpredictable points to on-demand; steady and predictable points to provisioned.
DynamoDB vs RDS
The choice the exam plants most is DynamoDB against a relational database:
- RDS / Aurora — relational data, SQL, complex joins across related tables.
- DynamoDB — flexible, schema-less data at massive scale, with fast key-based lookups and no joins.
Read the data shape. Joins across tables → RDS. Schema-less, huge scale, key lookups → DynamoDB. Typical DynamoDB use cases are high-traffic web and mobile apps: user profiles, session state, shopping carts.
One more fact: global tables
For multi-Region, low-latency access with a local copy everywhere, DynamoDB offers global tables, which replicate a table across Regions. That is distinct from RDS’s Multi-AZ and read replicas, which the exam may offer as distractors.
How to use the questions below
Answer each one before you reveal the explanation, and when you miss, read past the correct letter to why the other three fail. The distractors are always another data service — RDS where NoSQL belongs, Redshift or S3 offered for the wrong job. Matching the data shape to DynamoDB is the whole skill, and the reasoning below drills it. For the wider picture, see the databases overview.
Updated for CLF-C02 (July 2026). The sample questions above are our own work
in the style of the exam — not real exam items. The exam itself is set and marked
by the certification body.