mongodb如何去除重复数据

./mongo

var res=db.test.find();

while(res.hasNext()){

      var res1=db.test.find();

      var re=res.next();

      while(res1.hasNext()){

              var re1=res1.next();

              if(re.age==re1.age){

                   db.test.remove({"age":re1.age});

               }

       }

       db.test.insert(re);

}