code: function DBRef(namespace, oid, db) {
    if(!(this instanceof DBRef)) return new DBRef(namespace, oid, db);
    
    this._bsontype = 'DBRef';
    this.namespace = namespace;
    this.oid = oid;
    this.db = db;
  }
docs: A class representation of the BSON DBRef type.
  
  @class
  @param {string} namespace the collection name.
  @param {ObjectID} oid the reference ObjectID.
  @param {string} [db] optional db name, if omitted the reference is local to the current db.
  @return {DBRef}