MongoDB schema validation for unknown number of attributes?

Question

I want to save documents like this:

_id: ObjectId('63fdf80e4ab6021dad4ed24b')
data: {
 index: 1,
 time: 1000,
 dataFieldOne: 1.44
 dataFieldTwo: 2.752
 ...
 dataFieldN: 0.15
}

There can be any number of dataFieldN attributes, but I want to make sure that data object has at least one. For example, this would be an invalid document:

_id: ObjectId('63fdf80e4ab6021dad4ed24b')
data: {
 index: 1,
 time: 1000
}

Can I validate for this with MongoDB schema validation rules? If there is a solution, how efficient would it be?

Answer 1

Something like this?

db.createCollection(
"collection",
{
validator: {
  $jsonSchema: {
    bsonType: 'object',
    properties: {
      data: {
        bsonType: 'object',
        additionalProperties: false,
        required: [
          'dataFieldOne'
        ],
        properties: {
          index: {
            bsonType: 'double'
          },
          time: {
            bsonType: 'double'
          },
          dataFieldOne: {
            bsonType: 'double'
          }
        },
        patternProperties: {
          '^dataField.+$': {
            bsonType: 'double'
          }
        }
      }
    }
  }
}
});

Allows,

[
    {
        "data": {
            "index": 1,
            "time": 1,
            "dataFieldOne": 1
        }
    },
    {
        "data": {
            "index": 1,
            "time": 1,
            "dataFieldOne": 1,
            "dataFieldTwo": 1
        }
    }
]

Doesn't Allow

[
    {
        "data": {
            "index": 1,
            "time": 1
        }
    },
    {
        "data": {
            "index": 1,
            "time": 1,
            "ns": 1
        }
    },
    {
        "data": {
            "index": 1,
            "time": 1,
            "dataFieldTwo": 1
        }
    },
    {
        "data": {
            "index": 1,
            "time": 1,
            "dataFieldOne": 1,
            "ns": 1
        }
    }
]