MongoDB

MongoDB is a popular open-source NoSQL document database. Instead of tables and rows it stores data as flexible JSON-like documents (stored as BSON) grouped into collections, so records in the same collection can have different fields.

MongoDB supports rich queries, indexes, aggregation pipelines and transactions, and scales out with replication and sharding. It is widely used with Node.js applications, for example in the MERN stack (MongoDB, Express, React, Node.js).

db.users.insertOne({ name: "Asha", city: "Chennai", skills: ["java", "sql"] });
db.users.find({ city: "Chennai" });