Which scenario best describes usage of non-relational databases?

• A. Strict schemas and complex multi-table joins
• B. Fixed-size schema and SQL-based transactions
• C. Large volumes of unstructured data needing flexible schemas and horizontal scaling
• D. Only for storing small datasets

Answer: (C)

Non-relational databases are built for flexibility and scalability. They store data without enforcing a fixed schema, which makes it easy to evolve data models as requirements change. They excel with unstructured or semi-structured data (like JSON documents, logs, or sensor data) and support horizontal scaling across many servers, enabling high throughput and large-scale deployments. Because of this, they’re a good fit for workloads that require rapid ingestion, varying data shapes, and distributed architecture, rather than rigid multi-table schemas and complex joins typical of relational systems.

That’s why the scenario involving large volumes of unstructured data needing flexible schemas and horizontal scaling best describes using non-relational databases. The other options describe relational database characteristics: strict schemas with complex joins, fixed-size schemas with SQL-based transactions, or using databases only for small datasets.