db.diningmembers.find({modifedDate:{$type:9}}).forEach(function(x){x.tel = String(x.tel);db.diningmembers.save(x)});
http://www.linxh.blog.chinaunix.net/uid-15795819-id-3873422.html
Mongodb 字段类型转换
原文：http://www.cnblogs.com/luluzero/p/4875517.html
