Fundamental Principle of Higher Dimensional Graph Databases: Graph data is Isomorphic, and can store any other data structure within it algorithmically! For example: Key Value, Big Table / Column Oriented, & SQL / Relational Databases can all be in an "Query & Schema Translation layer" who's underlying storage is Graphs!
https://en.wikipedia.org/wiki/Isomorphism sch: https://www.google.com/search?q=isomorphic, https://www.google.com/search?q=isomorphic+mathematics