Which database does Facebook & Google use ?
Facebook has moved to a NoSQL database named HBase. Google uses their own system called BigTable. What is NoSQL ? NoSQL is a term used to designate databases which differ from classic relational databases. NoSQL database management systems are useful when working with a huge quantity of data when the data's nature does not require a relational model. The data can be structured, but NoSQL is used when what really matters is the ability to store and retrieve great quantities of data, not the relationships between the elements.