What is MongoDB and how is it different from relational databases?

Question

Accepted Answer

MongoDB is an open-source document-oriented NoSQL database . Stores data as flexible JSON-like documents ( BSON ) instead of rows in tables. Built for horizontal scaling and unstructured or evolving schemas. Documents over rows — one document holds nested objects and arrays; no joins for related data. Flexible schema — documents in the same collection can have different fields; no ALTER TABLE . Horizontal scaling — built-in sharding across nodes; relational databases scale up. No SQL, no joins — query API uses methods like find() ; $lookup handles join-like cases. Best for — content management, catalogs, IoT, analytics, anywhere schema evolves fast. Name 5 differences: documents vs rows, flexible vs fixed schema, embedding vs JOINs, horizontal vs vertical scaling, collections vs tables. Know when each is appropriate — do not be biased toward MongoDB.