title: mongorestore dropping collections using -drop option
body: <p>Suppose if I have a database testdb with two collections collA and collB and try to restore only collB from a dump.</p>
  
  <p>Will using --drop option with mongorestore drops both the existing collections (collA and collB) from testdb even though only collB is in the dump?</p>
  
  <p>I am using MongoDB 2.6.5</p>