MongoDB (from “humongous”) is a scalable, high-performance, open source, document-oriented database. It is written in C++. They built MongoDB from our own experiences building large scale, high availability, robust systems. They didn’t start from scratch, they really tried to figure out what was broken, and tackle that.

So the way about MongoDB is that if you take MySql, and change the data model from relational to document based, you get a lot of great features: embedded docs for speed, manageability, agile development with schema-less databases, easier horizontal scalability because joins aren’t as important. There are lots of things that work great in relational databases: indexes, dynamic queries and updates to name a few, and they haven’t changed much there.

Requirements: -
Demo: http://www.mongodb.org/
License: Creative Commons License