title: what is the benefit of the Fourth normal form?
body: <p>I googled a lot, but I did not found an answer to that question.</p>
  
  <p>The first three normal forms are common sense. They are used to save consistency and avoid anamalies. But why do we need the BCNF and the fourth normal form?</p>
  
  <p><em>(the fifth I do not even dare to ask, because I do not even understand what it does)</em></p>