Question

I managed to found out how to delete field but I have a problem It doesn’t really delete it it just set it to NULL.

db.user.update({'username': 'mezo', 'person': {'$in' : ['masidnadi241479214']}}, {'$unset': {'person.$': 1}})

My structure is something like that:

{
    "_id" : ObjectId("4ff14c7461d69af811000000"),
    "confirmed" : true,
    "person" : [
            null,
            null,
            "194724198274192",
            "3"
    ],
    "username" : "mezo"

}

Answer 1

Yeah, this behaviour is to be expected. To remove null elements from the array, run

 db.collection.update(query, {$pull: {'person': null}})

after that $unset operation.