NoSQL, with development led by Carlo Strozzi, is the latest and perhaps the most active in a line of implementations of the stream-operator database design originally described by Evan Shaffer, Rod Manis, and Robert Jorgensen in a 1991 Unix Review article and an associated paper.
The concept was originally described in a 1991 Unix Review article, and later expanded in a paper (see reference above), as well as in the book, "Unix Relational Database Management".