I concede that the relational model is the worst form of DBMS except for all those other forms that have been tried from time to time.
Bill Karvin – In Support of the Relational Model
I can’t agree more with that statement. Also I find software like CouchDb really interesting, it will not be the way to go. Beneath modeling, the main advantage of relational models is the flexible question startpoint (in terms of SQL it means the basic information you have beforehand to get the rest of what you need). If you know just a little about tree structure, the start point problem will be self-explaining. Accessing an upper node from a sub node just can’t be implemented as fast as accessing a flat structure and there relations.