How does a traditional relational database differ from a non-relational data storage system?

A traditional relational database (RDBMS) stores data in tables with a fixed schema (rows and columns), supports SQL for queries, and ensures data integrity through transactions and relationships between tables.

A non-relational data storage system (NoSQL) can use different data models: documents, key-value, graphs, column stores. It is more flexible in terms of schema, scales horizontally better, and is often used for large volumes of data or high write speeds.

Key differences:

• Schema: relational databases require a strict schema, NoSQL — flexible or absent.
• Data model: tables vs documents/key-value, etc.
• Scalability: relational often vertical, NoSQL — horizontal.
• Transactions: relational support ACID, NoSQL often sacrifices this for performance.

Example: MySQL — relational, MongoDB — document-oriented NoSQL.