om/mong.js

var db = db.getSiblingDB('omdb');

// Insert data in collections
load('mong_msg.js');
load('mong_tag.js');
load('mong_usr.js');

// Delete all collections + all records
//db.messages.drop(); db.tags.drop(); db.user.drop(); db.sessions.drop()

// Print all collections + records count
var collections = db.getCollectionNames();
print('Collections inside the db:');
for(var i = 0; i < collections.length; i++){
  var name = collections[i];

  if(name.substr(0, 6) != 'system')
    print(name + ' - ' + db[name].count() + ' records');
}