What is a document in MongoDB?

Short answer: How does it differ from rows in SQL databases?

Explain a bit more

A document in MongoDB is a record represented as a JSON-like object (BSON format) that contains field-value pairs. It can have a flexible structure, meaning each document in a collection may contain different fields and data types. Differences from SQL Rows: In SQL, a row is a fixed set of columns (defined by the schema), while in MongoDB, a document is more flexible and can vary in structure. A row in SQL is constrained by a schema, whereas a document in MongoDB can store complex, nested data structures (arrays, sub-documents).

Real-world example (ShopNest)

ShopNest’s SQL Server database stores customers, products, and orders. Good indexes and clear foreign keys keep checkout queries fast and safe.

Say this in the interview

1. Define — one clear sentence (the short answer above).
2. Example — relate it to a project like ShopNest or your real work.
3. Trade-off — when you would not use it.