title: Decimal(19,4) or Decimal(19.2) - which should I use?
body: <p>This sounds like a silly question, but I've noticed that in a lot of table designs for e-commerce related projects I almost always see decimal(19, 4) being used for currency.</p>
  
  <p>Why the 4 on scale? Why not 2? </p>
  
  <p>Perhaps I'm missing a potential calculation issue down the road?</p>