Intersystems Caché is:
  1. a post-relational database. Nobody seems to know what that means. It's better than the old-fashioned relational database model.
  2. The reincarnation of the mumps/M programming language
It has good support for sparse multidimensional arrays.

Intersystems Caché E2 Writeup, Copyright 2002 Frank Grimes.

This writeup is dedicated to the public domain. Do with it what you will. (For details, see http://creativecommons.org/licenses/publicdomain/ )

--Frank Grimes, 2007