MongoDBBackend & Data

MongoDB keeps each record as one self-contained document instead of spreading it across connected tables, so data that looks different from row to row fits without rearranging anything. Questions can reach inside nested fields and even inside lists, and a whole collection can be reshaped on the server before anything comes back. Copies on other machines keep it running when one fails, and a big dataset can be split across many servers. The price is weaker guarantees than PostgreSQL and stricter rules about indexes — for anything with real relationships I still pick PostgreSQL.