如何在MongoDB中高效地更新集合字段？

Question

I have dataset as

{"id":1,"Timestamp":"Mon, 11 May 2015 07:57:46 GMT","brand":"a"}
{"id":2,"Timestamp":"Mon, 11 May 2015 08:57:46 GMT","brand":"a"}

The expected result of data is

{"id":1,"Timestamp":ISODate("2015-05-11T07:57:46Z"),"brand":"a"}
{"id":2,"Timestamp":ISODate("2015-05-11T08:57:46Z"),"brand":"b"}

It means I want to revise the Timestamp in each row from string to ISODate My current code is

db.tmpAll.find().forEach(
    function (a) {
        a.Timestamp = new Date(a.Timestamp);
        db.tmpAll2.insert(a);
    }
);

It runs sucessfully, but it will take couple minutes to run the code and it need to create a new collection. Is there any efficient way to do it?

Answer 1

You don't need to create new collection. Use the collection.save method to update your document.

db.tmpAll.find().forEach(function(doc){
    doc.Timestamp = new Date(doc.Timestamp); 
    db.tmpAll.save(doc); 
})