javascript - How to update a field of collection efficient in MongoDB? -

i have dataset

{"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

{"id":1,"timestamp":isodate("2015-05-11t07:57:46z"),"brand":"a"} {"id":2,"timestamp":isodate("2015-05-11t08:57:46z"),"brand":"b"}

it means want revise timestamp in each row string isodate current code

db.tmpall.find().foreach(     function (a) {         a.timestamp = new date(a.timestamp);         db.tmpall2.insert(a);     } );

it runs sucessfully, take couple minutes run code , need create new collection. there efficient way it?

you don't need create new collection. use collection.save method update document.

db.tmpall.find().foreach(function(doc){     doc.timestamp = new date(doc.timestamp);      db.tmpall.save(doc);  })

Braziel