> db.data.update({\'name\': \'zero\'}, {\'$set\': {\'value\': 0}})
> db.data.findOne({\'name\': \'zero})
{\'name\': \'zero\', \'value\': 0.0}
If the value type is already double, then update the value with $set command can not change the value type double to int when using NumberInt() or NumberLong() function. So, to Change the value type, it must update the whole record.
var re = db.data.find({"name": "zero"})
re['value']=NumberInt(0)
db.data.update({"name": "zero"}, re)