[
    {
      "mode": "NULLABLE",
      "name": "bool_col",
      "type": "BOOLEAN"
    },
    {
      "mode": "NULLABLE",
      "name": "bytes_col",
      "type": "BYTES"
    },
    {
      "mode": "NULLABLE",
      "name": "date_col",
      "type": "DATE"
    },
    {
      "mode": "NULLABLE",
      "name": "datetime_col",
      "type": "DATETIME"
    },
    {
      "mode": "NULLABLE",
      "name": "geography_col",
      "type": "GEOGRAPHY"
    },
    {
      "mode": "NULLABLE",
      "name": "int64_col",
      "type": "INTEGER",
      "description": "Assumed to be have unique values."
    },
    {
      "mode": "REQUIRED",
      "name": "int64_too",
      "type": "INTEGER"
    },
    {
      "mode": "NULLABLE",
      "name": "numeric_col",
      "type": "NUMERIC"
    },
    {
      "mode": "NULLABLE",
      "name": "float64_col",
      "type": "FLOAT"
    },
    {
      "mode": "REQUIRED",
      "name": "rowindex",
      "type": "INTEGER",
      "description": "Assumed to be sequential integers."
    },
    {
      "mode": "REQUIRED",
      "name": "rowindex_2",
      "type": "INTEGER",
      "description": "Assumed to be a copy of the rowindex column."
    },
    {
      "mode": "NULLABLE",
      "name": "string_col",
      "type": "STRING"
    },
    {
      "mode": "NULLABLE",
      "name": "time_col",
      "type": "TIME"
    },
    {
      "mode": "NULLABLE",
      "name": "timestamp_col",
      "type": "TIMESTAMP"
    },
    {
      "mode": "NULLABLE",
      "name": "duration_col",
      "type": "INTEGER",
      "description": "#microseconds"
    }
  ]
