Updating an array of objects with a new key in mongoDB

Question

Similar to this question

Barrowing the data set, I have something similar to this:

{
    'user_id':'{1231mjnD-32JIjn-3213}',
    'name':'John',
    'campaigns':
        [
            {
                'campaign_id':3221,
                'start_date':'12-01-2012',
            },
            {
                'campaign_id':3222,
                'start_date':'13-01-2012',
            }
        ]
}

And I want to add a new key in the campaigns like so:

{
    'user_id':'{1231mjnD-32JIjn-3213}',
    'name':'John',
    'campaigns':
        [
            {
                'campaign_id':3221,
                'start_date':'12-01-2012',
                'worker_id': '00000'
            },
            {
                'campaign_id':3222,
                'start_date':'13-01-2012',
                'worker_id': '00000'
            }
        ]
}

How to insert/update a new key into an array of objects?
I want to add a new key into every object inside the array with a default value of 00000.

I have tried:
db.test.update({}, {$set: {'campaigns.worker_id': 00000}}, true, true)
db.test.update({}, {$set: {campaigns: {worker_id': 00000}}}, true, true)

Any suggestions?

Miguel Cartagena · Accepted Answer · 2012-12-21 10:48:34Z

2

I'm supposing that this operation will occur once, so you can use a script to handle it:

var docs = db.test.find();
for(var i in docs) {
    var document = docs[i];

    for(var j in document.campaigns) {
        var campaign = document.campaigns[j];
        campaign.worker_id = '00000';
    }

    db.test.save(document);
}

The script will iterate over all documents in your collection then over all campaigns in each document, setting the *worker_id* property. At the end, each document is persisted.

answered Dec 21, 2012 at 10:48

Miguel Cartagena

2,60618 silver badges20 bronze badges

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

2 Comments

user1460015 Over a year ago

I put the code into a file called addTo.js. Then in the mongo shell I have mongo addTo.js. The error follows: InternalError: too much recursion src/mongo/shell/collection.js:131. Is this the correct way?

Miguel Cartagena Over a year ago

How much documents you have in this collection? Maybe you should run the script many times, using skip and limit function to avoid this error.

Dmitry Zagorulkin · Accepted Answer · 2012-12-21 17:05:17Z

1

db.test.update({}, {$set: {'campaigns.0.worker_id': 00000}}, true, true

this will update 0 element.

if you want to add a new key into every object inside the array you should use: $unwind

example:

{
  title : "this is my title" ,
  author : "bob" ,
  posted : new Date() ,
  pageViews : 5 ,
  tags : [ "fun" , "good" , "fun" ] ,
  comments : [
      { author :"joe" , text : "this is cool" } ,
      { author :"sam" , text : "this is bad" }
  ],
  other : { foo : 5 }
}

unwinding tags

db.article.aggregate(
    { $project : {
        author : 1 ,
        title : 1 ,
        tags : 1
    }},
    { $unwind : "$tags" }
);

result:

{
     "result" : [
             {
                     "_id" : ObjectId("4e6e4ef557b77501a49233f6"),
                     "title" : "this is my title",
                     "author" : "bob",
                     "tags" : "fun"
             },
             {
                     "_id" : ObjectId("4e6e4ef557b77501a49233f6"),
                     "title" : "this is my title",
                     "author" : "bob",
                     "tags" : "good"
             },
             {
                     "_id" : ObjectId("4e6e4ef557b77501a49233f6"),
                     "title" : "this is my title",
                     "author" : "bob",
                     "tags" : "fun"
             }
     ],
     "OK" : 1
}

After you could write simple updaiting query.

edited Dec 21, 2012 at 17:05

answered Dec 21, 2012 at 9:13

Dmitry Zagorulkin

8,5584 gold badges39 silver badges63 bronze badges

6 Comments

user1460015 Over a year ago

Adding a new key must be done through a script and not through the mongo shell?

Dmitry Zagorulkin Over a year ago

If you can do it through mongo shell that means you can use it through each mongo driver.

user1460015 Over a year ago

Can you do it through the mongo shell? As far as I know aggregate doesn't modify the database but outputs a document that is requested. I want to modify the actual db.

Dmitry Zagorulkin Over a year ago

it's just example. i had want to get you a point for solving your problem. api.mongodb.org/python/current/examples/aggregation.html

user1460015 Over a year ago

I understand and thank you but I was looking for something that modifies the document through the mongo shell. I am sure this problem is solvable applying a script but I would like to use the mongo shell directly.

|

Collectives™ on Stack Overflow

Updating an array of objects with a new key in mongoDB

2 Answers 2

2 Comments

6 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

6 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related