title: In Ruby on Rails, what's the difference between DateTime, Timestamp, Time and Date?
body: <p>In my experience, getting dates/times right when programming is always fraught with danger and difficulity. </p>
  
  <p>Ruby and Rails have always eluded me on this one, if only due to the overwhelming number of options; I never have any idea which I should pick.</p>
  
  <p>When I'm using Rails and looking at ActiveRecord datatypes I can find the following</p>
  
  <blockquote>
    <p>:datetime, :timestamp, :time, and :date</p>
  </blockquote>
  
  <p>and have no idea what the differences are or where the gotchas lurk.</p>
  
  <p>What's the difference? What do you use them for? </p>
  
  <p>(P.S. I'm using Rails3)</p>