MongoDB update all subelements from subarray

Question

I have a collection with a following schema:

{
    "_id" : ObjectId("52dfba46daf02aa4630cf529"),
    "hotelVenue" : {
        "rooms" : [ 
            {
                "clientId" : "ROOM_1",
                "roomName" : "Executive"
            }, 
            {
                "clientId" : "ROOM_2",
                "roomName" : "Premium"
            }
        ]
    }
},
{
    "_id" : ObjectId("52dfc2f9daf02aa2632bc8af"),
    "hotelVenue" : {
        "rooms" : [ 
            {
                "clientId" : "ROOM_1",
                "roomName" : "Studio Room"
            }, 
            {
                "clientId" : "ROOM_2",
                "roomName" : "Soho Suite"
            }, 
            {
                "clientId" : "ROOM_3",
                "roomName" : "Luxury Suite"
            }
        ]
    }
}

I need to genearate unique id for all the records -> subarray. i.e., in the example there is rooms so for each and every room type, I need give a unique id basically using ObjectId().

Output should look something like the below, where roomId being generated.

{
    "_id" : ObjectId("52dfba46daf02aa4630cf529"),
    "hotelVenue" : {
        "rooms" : [ 
            {
                "clientId" : "ROOM_1",
                "roomName" : "Executive",
                "roomId" : "56f8cb3f0c658b4bc26172342"
            }, 
            {
                "clientId" : "ROOM_2",
                "roomName" : "Premium",
                "roomId" : "56f8cb3f0c658b4bc26176d4"
            }
        ]
    }
}

I have written this script where it gives the following error: Error: Line 9: Unexpected token +

db.venues.find().forEach(function(data) 
{
    data.hotelVenue.rooms.forEach(function(roomItem) 
    {
        db.venues.update({_id:data._id,'data.hotelVenue.rooms.clientId' : roomItem.clientId},
        {
            $set:
            {
                'hotelVenue.rooms.'+roomItem.clientId+'.roomId' : ObjectId()
            }
        }); 
    });
})

Joachim Isaksson · Accepted Answer · 2016-03-28T09:25:34.193

1

EDIT: This should do it in a more efficient manner by only saving each document once;

db.venues.
  find({"hotelVenue.rooms": { $elemMatch: {roomId: {$exists: 0}}}}).
  forEach(function(doc) {
    doc.hotelVenue.rooms.forEach(function(room) {
      if(!room.roomId) {
        room.roomId = ObjectId();
      }
    }); 
    db.venues.save(doc);
  });

The find filters out only documents that are in need of updating. After that, it's just a matter of updating the document as needed and calling save.

Of course, backups are in order before running potentially destructive queries from random people on the Internet against your production data set.

edited Mar 28 '16 at 09:25

answered Mar 28 '16 at 07:31

Joachim Isaksson

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Joachim, when i run the query which you have provided its gives the error has **TypeError: result has no properties (shell):7** – Sharath Mar 28 '16 at 07:38
@sharath Which version of mongodb are you using? – Joachim Isaksson Mar 28 '16 at 07:39
version : 2.6.10. Running this in ubuntu''s robomongo – Sharath Mar 28 '16 at 07:40
doing it locally as of now if everything works fine, then i'll run on production db – Sharath Mar 28 '16 at 07:44
ya sure, i'll be waiting for your reply – Sharath Mar 28 '16 at 08:20
@Sharath Works for me on 2.6.11 using the mongo shell. Don't have robomongo to test with. If you can't make it work, you may want to look at the question this was marked as a duplicate of. – Joachim Isaksson Mar 28 '16 at 09:10
Thanks Joachim, i'll take a look into it. – Sharath Mar 28 '16 at 09:19
@Sharath Updated with a version that - once again - works for me on 2.6, you may want to take a look. – Joachim Isaksson Mar 28 '16 at 09:27
Thanks Joachim, it works... – Sharath Mar 28 '16 at 12:51

MongoDB update all subelements from subarray

1 Answers1