[
    {
      "mode": "NULLABLE",
      "name": "user_id",
      "type": "STRING"
    },
    {
      "mode": "NULLABLE",
      "name": "item_id",
      "type": "INT64"
    },
    {
      "mode": "NULLABLE",
      "name": "rating",
      "type": "FLOAT"
    }
]
