Finding Sub-documents through dot notation in mongodb

Question

I have a simplified collection structure below for simplicity's sake. I am unable to query the specific sub-documents under the profile field.

For example, I want to find the sub-document "profiles.Bernie". Is there a find() query that will allow me to only retrieve the document for Bernie (i.e. category and id for Bernie)? Apologies if this is a duplicate, but I was unable to find solutions that catered the way this collection is structured below

{
        "_id" : ObjectId("56aec822ceb6e9dc23d32271"),
        "sm_user" : "user1",
        "profiles" : {
                "Bernie" : {
                        "category" : "Politics",
                        "id" : "bernie"
                },
                "Hilary" : {
                        "category" : "Politics",
                        "id" : "hilary"
                }
        }
}

Joachim Isaksson · Accepted Answer · 2016-02-15 16:57:44Z

1

Yes, you can choose to just get the Bernie subtree and suppress the normally included _id;

db.test.find({},{ _id:0, "profiles.Bernie":1 })

This will include the structure leading up to Bernie (aka the profiles tag), but only the data from that subtree.

If you don't want the structure to remain, you could also use the aggregate framework to project Bernie to the root of the output document;

db.test.aggregate([{$project: { _id:0, 'Bernie': "$profiles.Bernie"}}])

edited Feb 15, 2016 at 16:57

answered Feb 15, 2016 at 16:49

Joachim Isaksson

182k28 gold badges298 silver badges308 bronze badges

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

1 Comment

cynical biscuit Over a year ago

That's perfect, I was having a brain fart. I forgot about the projection parameters. Thanks so much!

Collectives™ on Stack Overflow

Finding Sub-documents through dot notation in mongodb

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related