curl --request GET \
  --url https://cloud.cdata.com/api/primaryKeys \
  --header 'Authorization: Basic <encoded-value>'

{
  "results": [
    {
      "affectedRows": 123,
      "schema": [
        {
          "catalogName": "<string>",
          "columnLabel": "<string>",
          "columnName": "<string>",
          "dataTypeName": "<string>",
          "length": 123,
          "nullable": true,
          "ordinal": 123,
          "precision": 123,
          "scale": 123,
          "schemaName": "<string>",
          "tableName": "<string>"
        }
      ],
      "rows": [
        [
          "<unknown>"
        ]
      ]
    }
  ],
  "error": {
    "message": "<string>"
  }
}