Can't query field when schema contains nested arrays

MongoDB Atlas App Services & Realm
,
1

Hi,

I’ve been struggling with an issue with my schema that contains arrays of arrays. While the schema validates, I always get an error Cannot query field \"events\" on type \"MyFieldType".

I’m trying to use this:

"events": {
                    "bsonType": "array",
                    "items": {
                      "bsonType": "array",
                      "items": {
                        "bsonType": "string"
                      }
                    }
                  }

The raw data for this looks as expected e.g.:

"events" : [
                        [
                            "101",
                            "404",
                            "625"
                        ]
                    ]

Is the issue here nested arrays, are they not supported? Note that the schema generator also produces this output.

2

This should have been posted in the Atlas GraphQL API section (I can’t edit it)

4

So for anyone else with this issue, I guess this isn’t possible despite the schema generator producing this output.

Simplified by creating a new collection and added this document:

{
    "_id" : ObjectId("633603c8a4e9837b18a0459d"),
    "events" : [
        [
            "101",
            "404",
            "625"
        ],
        [
            "201",
            "204",
            "225"
        ]
    ]
}

Then used the following GraphQL schema generator, which generated this schema:

{
  "title": "test",
  "properties": {
    "_id": {
      "bsonType": "objectId"
    },
    "events": {
      "bsonType": "array",
      "items": {
        "bsonType": "array",
        "items": {
          "bsonType": "string"
        }
      }
    }
  }
}

While this works;

query MyQuery {
  test {
    _id
  }
}

This query:

query MyQuery {
  test {
    _id,
    events
  }
}

returns "message": "Cannot query field \"events\" on type \"Test\".",

6

Hi @Gareth_Davies, welcome to the community. :wave:
Querying arrays of arrays using the Atlas GraphQL API is not supported as of now. We already have a feature request logged in for this. Please upvote the same if you’d like to have this in our GraphQL API.

However, for now you can create a custom resolver to achieve the same that resolves the request to an array you expect.
Here’s a step-by-step tutorial that elaborates the complete process of creating a custom resolver:

If you have any doubts, please feel free to reach out to us.

Thanks and Regards.
Sourabh Bagrecha,
MongoDB

8

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