Came across these excellant 2 diagrams from 2 very interesting blog posts.
“NewSQL-as-a-Service” Cloud Database
This diagram shows where all the main database engines fit into the wider data management landscape. Taken from http://xeround.com/blog/2011/04/newsql-cloud-database-as-a-service although the original article NoSQL, NewSQL and Beyond: The answer to SPRAINed relational databases is by Matthew Aslett which is part of the The 451 Group’s new long format report on emerging database alternatives, NoSQL, NewSQL and Beyond.
Don’t Become a One-trick Architect
This article by Thomas Kejzer gives an historical look at architectures and data http://blog.kejser.org/2011/12/08/dont-become-a-one-trick-architect/#more-377
This is the evolutionary tree of life for data storage engines