MongoDB

MongoDB is a document-oriented NoSQL database used for high volume data storage. Instead of using tables and rows as in the traditional relational databases, MongoDB makes use of collections and documents. Documents consist of key-value pairs which are the basic unit of data in MongoDB. Collections contain sets of documents and function which is the equivalent of relational database tables.

MongoDB Features

• Each database contains collections which in turn contains documents. Each document can be different with a varying number of fields. The size and content of each document can be different from each other.
• The document structure is more in line with how developers construct their classes and objects in their respective programming languages. Developers will often say that their classes are not rows and columns but have a clear structure with key-value pairs.
• The rows (or documents as called in MongoDB) doesn't need to have a schema defined beforehand. Instead, the fields can be created on the fly.
• The data model available within MongoDB allows you to represent hierarchical relationships, to store arrays, and other more complex structures more easily.

RDBMS Vs NoSQL

RDBMS	NoSQL
It is a structured data that provides more functionality but gives less performance.	Structured or semi structured data, less functionality and high performance.