[source, ruby]
----
response = client.indices.create(
  index: 'my-index-000001',
  body: {
    mappings: {
      properties: {
        my_join_field: {
          type: 'join',
          relations: {
            question: 'answer'
          },
          eager_global_ordinals: false
        }
      }
    }
  }
)
puts response
----
