How to remove a particular element from a nested array in mongodb

Question

My Document structure is

"MainAccounts" : [ 
    {
        "orgs" : "5808ba773fe315441b9e0a9e",
        "_id" : ObjectId("5808bc0c3fe315441b9e0b1a"),
        "accounts" : [ 
            "5808baf33fe315441b9e0aa7", 
            "5808baf33fe315441b9e0aa8", 
            "5808baf33fe315441b9e0aa9", 
            "5808baf33fe315441b9e0aa1"
        ]
    },
     {
        "orgs" : "5808ba773fe315441b9e0a9f",
        "_id" : ObjectId("5808bc0c3fe315441b9e0b1b"),
        "accounts" : [ 
            "5808baf33f35425852s255s7", 
            "5808baf3sd23s2d3d4w5s2s8", 
            "5808baf33sd211ds2d2sdsa9", 
            "5808baf33dssd2d21b9e0aa1"
        ]
    }
],

I want to pull out a particular account say "5808baf33fe315441b9e0aa8" from this, i wrote the query like this.

{ $pull: { "MainAccounts.$.accounts": "5808baf33fe315441b9e0aa8"} }

It gives only error as "The positional operator did not find the match needed from the query. Unexpanded update: MainAccounts.$.accounts"

 { $pull: { "MainAccounts.0.accounts": "5808baf33fe315441b9e0aa8" } }

If i give like this it will remove that value only which gives the expected output.

i need output as

 "MainAccounts" : [ 
    {
        "orgs" : "5808ba773fe315441b9e0a9e",
        "_id" : ObjectId("5808bc0c3fe315441b9e0b1a"),
        "accounts" : [ 
            "5808baf33fe315441b9e0aa7",                 
            "5808baf33fe315441b9e0aa9", 
            "5808baf33fe315441b9e0aa1"
        ]
    },
     {
        "orgs" : "5808ba773fe315441b9e0a9f",
        "_id" : ObjectId("5808bc0c3fe315441b9e0b1b"),
        "accounts" : [ 
            "5808baf33f35425852s255s7", 
            "5808baf3sd23s2d3d4w5s2s8", 
            "5808baf33sd211ds2d2sdsa9", 
            "5808baf33dssd2d21b9e0aa1"
        ]
    }
],

here i am not able to delete value from second array i need to give

 { $pull: { "MainAccounts.1.accounts": "5808baf33fe315441b9e0aa8" } }

But i need to loop through, any help is appreciated.

What is `someId`? The positional `$` operator usage is correct, but the requirement for that to work is actually matching the element in the "query" part, which is what should be in `someId`. What is `MainAccounts`? is that actually part of the collection or part of your document? If part of the document, then we have other problems here. — Neil Lunn, May 24 '17 at 05:17
try this one : collection.update(someId, { $pull: { "MainAccounts.accounts": req.params.accountId } }) — Dinesh undefined, May 24 '17 at 06:06
@Neil Lunn Please leave all the things "someId". kindly consider my $pull -query. how can i pull out a particular element from that nested array- { $pull : {"MainAccounts.$.accounts" : "5808baf33fe315441b9e0aa8" } } — arunraj770, May 24 '17 at 08:38
Refer to https://stackoverflow.com/questions/5228210/how-to-remove-an-element-from-a-doubly-nested-array-in-a-mongodb-document — Pranoy Gn, Jul 01 '19 at 10:07

score 1 · Answer 1 · answered Aug 30 '18 at 15:24

1

You will get an error: "Cannot apply $pull to a non-array value"

This should be :

db.collection.update({'MainAccounts.accounts': '5808baf33fe315441b9e0aa8'}, {$pull: {MainAccounts:{ accounts: '5808baf33fe315441b9e0aa8'}}})

Here is a reference to this:

mongodb Cannot apply $pull/$pullAll modifier to non-array, How to remove array element

answered Aug 30 '18 at 15:24

Matt Kuhns

1,328
1
13
26

The above command will remove the whole nested json(orgs, _id, accounts) not just 5808baf33fe315441b9e0aa8 – Pranoy Gn Jul 01 '19 at 10:00

score -1 · Answer 2 · answered May 24 '17 at 07:59

-1

db.collection.update({someId,{$pull : {"MainAccounts":{"accounts":"5808baf33fe315441b9e0aa8"}}}})

someId could be your _id. Remember if you have to access the document inside the array you cant access it without . operator only.You have to use the index with it.The other way mongodb can access it is by the use of braces.

answered May 24 '17 at 07:59

aaditya

555
7
19

1

Hi This one also removes all the accounts array elements instead of only 5808baf33fe315441b9e0aa8. – arunraj770 May 24 '17 at 08:53

score -1 · Answer 3 · answered May 24 '17 at 13:55

-1

This will do what you want:

db.collection.update({'MainAccounts.accounts': '5808baf33fe315441b9e0aa8'}, {$pull: {'MainAccounts.$.accounts': '5808baf33fe315441b9e0aa8'}})

answered May 24 '17 at 13:55

Andrew Winterbotham

1,000
7
13

This also does the same, account array consisting of `5808baf33fe315441b9e0aa8` is getting removed – arunraj770 May 26 '17 at 04:05
I don't understand what you are trying to do. You wrote that removing that value only gives the expected output and the above code will do that. – Andrew Winterbotham May 26 '17 at 19:09
Hi andrew, this code gives `"MainAccounts" : [ { "orgs" : "5808ba773fe315441b9e0a9e", "_id" : ObjectId("5808bc0c3fe315441b9e0b1a"), "accounts" : [ ] },` but what i need is to remove only that particular value `"MainAccounts" : [ { "orgs" : "5808ba773fe315441b9e0a9e", "_id" : ObjectId("5808bc0c3fe315441b9e0b1a"), "accounts" : [ "5808baf33fe315441b9e0aa7", "5808baf33fe315441b9e0aa9", "5808baf33fe315441b9e0aa1" ] },}` , this is what i need – arunraj770 May 29 '17 at 04:43
See my answer. I got a "Cannot apply $pull to a non-array value" when doing this one. – Matt Kuhns Aug 30 '18 at 15:28

How to remove a particular element from a nested array in mongodb

3 Answers3