title: In which normal form are these FDs?
body: <p>I've been trying to figure out the difference between the 2nd and 3rd Normal Form using this example. The definitions didn't do the trick for me...</p>
  
  <p>These are the functional dependencies:</p>
  
  <pre><code>A is the candidate key. (A --&gt; A,B,C,D)
  FDs:
  A --&gt; CD
  AC --&gt; D
  CD --&gt; B
  D --&gt; B
  </code></pre>
  
  <p>My idea: it's in 1st and 2nd, but not in 3rd Normal form because A, the candidate key, doesn't consist of two or more columns. But B is transitively dependent on D. So it's not in 3rd.</p>
  
  <p>Ist that correct? Especially the argument that A consits of less than two columns?</p>