title: Why do we need a temporal database?
body: <p>I was reading about temporal databases and it seems they have built in time aspects. I wonder why would we need such a model?</p>
  
  <p>How different is it from a normal RDBMS? Can't we have a normal database i.e. RDBMS and say have a trigger which associates a time stamp with each transaction that happens? May be there would be a performance hit. But I'm still skeptical on temporal databases having a strong case in the market.</p>
  
  <p>Does any of the present databases support such a feature?</p>