命令行修改集合內字段的數據類型:
db.collection.find().forEach(function (x) {
x.filed1 = parseInt(x.filed1); # parseInt 轉爲double
x.filed2 = NumberInt(x.filed2); # NumberInt 轉爲int
x.filed3 = new ISODate(x.filed3); # ISODate 轉爲Date
db.collection.save(x);
});