title: Difference between a row-oriented and column-oriented databases in dealing information retrieval
body: <p>Recently, I started working on HBase (one of the column-oriented databases). While going through the source code, one question keeps popping in my head. Thought of asking this.
  My question is, how exactly a row-oriented database deals with information retrieval (say a select query) and how different is that when comes to column-oriented database.
  And how different these databases store data in the underlying flat files ( at the end of day, every database uses files).</p>
  
  <p>Please do correct me in case I went wrong in any part of this question.</p>
  
  <p>Regards,
  Krishna</p>