I have a document which looks like this

{
 _id:1,
 list_id:23,
 name:'list01'
 cards:[
  {
   id:3,
   name:'card01'
   categories:[{
    id:10,
    category:'section01',
    tags:[{id:11,name:'tag01',is_selected: true}]
  }] 
  }
 ]
}

I need to insert/push some data to tags array in a selected category for a given list_id but I'm getting an error saying

MongoError: Too many positional (i.e. '$') elements found in path 'cards.$.categories.$.tags'

This is the query that I have tried out. What's wrong with this query any idea on how to achieve this?

db.collection(TABLE)
    .updateOne(
      { list_id: 23, 'cards.categories.category': 'section01'},
      { $push: { 'cards.$.categories.$.tags': { name: 'tag02', id: uuidv4(), is_selected: true } } }
    );

Solution 1

You can not use multiple $ positional, for your case you can use single positional and arrayFilters,

The filtered positional operator $[<identifier>] identifies the array elements that match the arrayFilters conditions for an update operation,

db.collection(TABLE).updateOne({
  list_id: 23,
  "cards.categories.category": "section01"
},
{
  $push: {
    "cards.$.categories.$[elem].tags": {
      name: "tag02",
      id: uuidv4(),
      is_selected: true
    }
  }
},
{
  arrayFilters: [
    { "elem.category": "section01" }
  ]
})

Playground

Solution 2

In short, it is not possible.

Nested Arrays

The positional $ operator cannot be used for queries which traverse more than one array, such as queries that traverse arrays nested within other arrays, because the replacement for the $ placeholder is a single value

https://docs.mongodb.com/manual/reference/operator/update/positional/

However, you may want to try $[]

Nested Arrays The filtered positional operator $[] can be used for queries which traverse more than one array and nested arrays.

For an example, see Update Nested Arrays in Conjunction with $[].

https://docs.mongodb.com/manual/reference/operator/update/positional-filtered/#position-nested-arrays-filtered

Solution 3

You can use $[identifier]

db.collection.update({
  "list_id": 23,
  "cards.categories.category": "section01"
},
{
  $push: {
    "cards.$.categories.$[elem].tags": {
      name: "tag02",
      id: uuidv4(),
      is_selected: true
    }
  }
},
{
  arrayFilters: [
    {
      "elem.category": "section01"
    }
  ],
  multi: true
})

try it here