SQL and NoSQL are Two Sides of the Same Coin

An anonymous reader writes "NoSQL databases have become a hot topic with their promise to solve the problem of distilling valuable information and business insight from big data in a scalable and programmer-friendly way. Microsoft researchers Erik Meijer and Gavin Bierman ... present a mathematical model and standardized query language that could be used to unify SQL and NoSQL data models." Unify is not quite correct; the article shows that relational SQL and key-value NoSQL models are mathematically dual, and provides a monadic query language for what they have coined coSQL.