Which statement is true about relational databases?

• A. They store data as documents with flexible schemas
• B. They use tables with fixed schemas and support SQL, ideal for structured data and transactions
• C. They scale only vertically and do not support SQL
• D. They are primarily for unstructured data analytics

Answer: (B)

Relational databases organize data into tables with fixed schemas and use SQL to query and manage the data, which makes them well suited for structured data and transactional workloads. The predefined schema enforces data types and relationships, and ACID properties ensure reliable, consistent updates across operations. While many relational systems scale by adding resources to a single server (vertical scaling), they do support SQL and are designed around structured data and transactions. The other statements describe non-relational approaches—document stores with flexible schemas, or systems focused on unstructured analytics—or claim no SQL support, which doesn’t fit relational databases.