My assertion means that relational algebra without Cartesian product operator can be used for noSQL databases, except graph databases. Primitive operators of re

My assertion means that relational algebra without Cartesian product operator can be used for noSQL databases, except graph databases. Primitive operators of relational algebra such as projection, selection and set operators are pretty much scalable. Cartesian product is not. Authors mentioned that property of the Cartesian product in the example with WWW database. In order to emulate Cartesian product in noSQL developers have to use external tools such as Map Reduce which has nothing to do with databases. http://typicalprogrammer.com/?p=16 http://typicalprogrammer.com/?p=16