title: What do MongoDB oplog operations letters mean?
body: <p>What are different letters in MongoDB oplog "op" field means ? I can guess some of the letters meaning but I am not sure.</p>
  
  <p>"n" = ?</p>
  
  <p>"i" = insert , is this correct ?</p>
  
  <p>"u" = update, is this correct ?</p>
  
  <p>"c" = count, is this correct ?</p>
  
  <p>I guess "d"= delete ? </p>
  
  <p>what are other letters are there and what are their meanings ? </p>