Need help with query for subobject

Drivers & ODMs
#1

Hello, I am a new to MongoDB and I seeking help.

I have a document in my collection that looks like this:

_id:5f2f40b8d1287d5c98309cb9
foo: "Some value"
zed: "Another Thing"
items: Object
    item_16414803554: Object
        name: "Some Name"
        age: "45"
    item_16414806548: Object
        name: "Some Name"
        age: "45"

I am using mongojs to work with the data and I need to remove one of the sub objects like “item_16414806548”. I cannot figure out what the query should be to do so.

I tried this:

db.mycollection.remove({_id: mongojs.ObjectId(id)}, {items: {_id: {$eq: itemid }}}, function(err, doc) {
res.json(doc);
});

But that’s not working. Can anyone tell me what the proper query would be? Thanks for any help!

#2

Hi, .remove() will actually remov the whole document, not part of document. What you might want to do is to update a document to set/unset a key in it.
Try - .updateOne({//matching conditions}, {$unset:{"items.item_16414806548": ""}})
This will unset (update the document to remove that key) the key, and when you write it in dot notation, it can access the internal key item_16414806548 from items.
Checkout - $unset

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#3

Thank you! Going to give that a try! Is there a way I can pass the items.item_16414806548 in as a variable. I cannot seem to put a variable in there to save my life. Thanks again for responding!

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#4

Try -

key_var = "items.item_16414806548"
db.coll.updateOne({/*matching conditions*/}, {$unset:{ key_var : ""}})
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#5

Ok, I will! Thanks again!

#6

Just wanted to let you know that your advice was greatly appreciated! Because of you I got it to work. Thank you so much!!

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