MongoDB is one of the most popular NoSQL database management systems today. As against the traditional RDBMS, it stores the data in an unnormalized way, in binary JSON format.

MongoDB is an open-source document database. The name is derived from Humongous DB. This falls into the category of NoSQL databases. The data in MongoDB is stored in an un-normalized format, as a collection of documents. A collection in MongoDB is equivalent to a table in RDBMS and a document is equivalent to a record. However, unlike a record, a document need not have the same structure as other documents in the same collection.