Update particular field in mongodb of all documents with reference to its current value

Question

In my mongodb collection, i have all documents stored with "TimeStamp" field in 'MM-DD-YYYY' format which was stored as string. I want to update that exiting TimeStamp field to 'DD-MM-YYYY' format in all documents. Can anyone help me writing a query for that.

Example I have documents as below

{
  "id" : "1",
  "TimeStamp" : "09-22-2018"
},
{
  "id" : "2",
  "TimeStamp" : "09-23-2018"
}

I want to update them to

{
  "id" : "1",
  "TimeStamp" : "22-09-2018"
},
{
  "id" : "2",
  "TimeStamp" : "23-09-2018"
}

Could you post sample collection and the version you are using — Ashh
– Ashh, Commented Sep 23, 2018 at 7:34

Adi Levin · Accepted Answer · 2018-09-23 08:11:32Z

1

You can iterate over all documents and reformat the TimeStamp as follows:

function reformat(date) { 
  var parts = date.split('-'); 
  return parts[1]+'-'+parts[0]+'-'+parts[2]; 
}

db.collection.find({TimeStamp : {$exists: true}}).snapshot().forEach(
 function (doc) { 
   db.collection.update( 
     { _id: doc._id }, 
     { $set: { TimeStamp: reformat(doc.TimeStamp) }}
   ); 
 }
);

answered Sep 23, 2018 at 8:11

Adi Levin

5,3031 gold badge19 silver badges26 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Ashh · Accepted Answer · 2018-09-23 07:53:05Z

0

You can try below $out aggregation

db.collection.aggregate([
  { "$addFields": {
    "TimeStamp": {
      "$dateToString": {
        "format": "%d-%m-%Y",
        "date": { "$dateFromString": { "dateString": "$TimeStamp", "format": "%m-%d-%Y" }}
      }
    }
  }},
  { "$out": "collection_name" }
])

answered Sep 23, 2018 at 7:53

Ashh

46.6k16 gold badges111 silver badges137 bronze badges

Collectives™ on Stack Overflow

Update particular field in mongodb of all documents with reference to its current value

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related