What are the differences between relational and non-relational databases?

Relational databases (RDBMS) and non-relational databases (NoSQL) differ in data storage structure and methods of operation:

• Relational databases:

  • Store data in tables with a fixed schema (rows and columns).
  • Use SQL language for queries.
  • Ensure transactional integrity and data consistency (ACID).
  • Suitable for complex queries and linked data.

• Non-relational databases:

  • Can store data in various formats: documents (JSON), key-value, graphs, column stores.
  • Flexible or absent schema.
  • Often focused on scalability and high performance.
  • May sacrifice strict transactional properties for speed and scalability (BASE).

Example: MongoDB — document-oriented NoSQL database, PostgreSQL — relational database.

The choice depends on data requirements, load, and operation types.