'[D]ue to their horrendous complexity and 
inflexibility, databases and DBMSs relying on the hierarchical model became 
obsolete  in the 80's, at least technologically. SQL DBMSs based ... 
on the simpler relational data model, based on predicate logic and set 
mathematics proved superior. ...What is the justification, then, for choosing a 
more complex, discredited data model for data exchange, when a majority of 
commonly used DBMSs employ a simpler, sounder and, thus, superior data 
model?'

   
  Well, speaking of complexity.... I'm largely a document person, and much of my 'data-side' 
  experience has been bibliographic. And frankly, doing so using an RDBMS has 
  frequently felt like programming a Turing machine. Sure you can do anything 
  that way, and you know you can. But it sure is the hard way. This is complex 
  multidemsional __information__ and splitting it into 2D tables is work, and 
  then getting it back in a useful way is a major task for the 
  server.
   
  I 
  also have to be skeptical of his charges of inflexibilty: The inflexibility of 
  the relational DBAs has uniformly been a major stumbling block: It seems to 
  take an order from the CEO countersigned by Codd to make a trival change in 
  the schema.
   
  So 
  IMO, if we're insulting people, I suggest that RDBMS are wonderfully designed 
  for beancounting, and that as soon as you try to start dealing with the real 
  world instead of making the world deal with your data structures, an RDBMS 
  doesn't look so wonderful.
   
  Frank