There's been a quite revolution going on in the world of databases. After dominating for years, the monopoly of relational databases is ending.
Loosely encompassing everything 'not SQL' -- read "not relational" -- No SQL databases began emerging in the 2000s, birthed in the convergence of cloud computing, web services, and big data. Led by pioneering work of Google, Amazon, and others to create databases that could scale to massive clusters of commodity computer hardware, NoSQL is now a loose term encompassing all databases that don't model and access data in the same way relational databases do.
While relational databases may continue to be a good fit for many enterprise apps, and NoSQL databases are appreciably more complex to develop and manage, No SQL databases can offer opportunities to enterprises needing to collect huge amounts of data. In fact, the trend is to collect as much data as possible -- even before knowing how it can be used -- to fuel future enterprise data mining and AI applications seeking competitive advantage. It's therefore prudent to prepare for NoSQL having a place alongside relational databases within your enterprise.