title: Truncate a collection
body: <p>How do I truncate a collection in MongoDB or is there such a thing?</p>
  
  <p>Right now I have to delete 6 large collections all at once and I'm stopping the server, deleting the database files and then recreating the database and the collections in it. Is there a way to delete the data and leave the collection as it is? The delete operation takes very long time. I have millions of entries in the collections.</p>