如何從json文件中獲取表架構：parse_table_schema_from_json？

Question

我正在嘗試from apache_beam.io.gcp.bigquery import parse_table_schema_from_json使用parse_table_schema_from_json獲取表架構，從此處 from apache_beam.io.gcp.bigquery import parse_table_schema_from_json

這是我的代碼：

 def getSchema(pathToJSON):
    with open(pathToJSON) as data_file:
        schema_data = json.dumps(json.load(data_file))
    table_schema = parse_table_schema_from_json(schema_data)
    # print(table_schema)
    return table_schema

這是我得到的錯誤：

    Traceback (most recent call last):
  File "test_get_schema.py", line 16, in <module>
    getSchema("vauto_table_schema.json")
  File "test_get_schema.py", line 13, in getSchema
    table_schema = parse_table_schema_from_json(schema_data)
  File "/home/usr/.local/lib/python2.7/site-packages/apache_beam/io/gcp/bigquery.py", line 269, in parse_table_schema_from_json
    fields = [_parse_schema_field(f) for f in json_schema['fields']]
TypeError: list indices must be integers, not str

我的json文件如下所示：

[
  {
    "name": "StockNumber",
    "type": "INTEGER",
    "mode": "NULLABLE"
  },
  {
    "name": "Product",
    "type": "STRING",
    "mode": "NULLABLE"
  }
]

我想念什么？

Answer 1

您需要字典而不是列表。 修改您的函數和架構文件，如下所述，然后重試

  def getSchema(pathToJSON):
    schema_data = json.dumps(json.load(open("mapping.json")))
    table_schema = parse_table_schema_from_json(schema_data)
    # print(table_schema)
    return table_schema

您的架構文件應為

{
  "fields": [
   {
    "type": "INTEGER",
    "name": "StockNumber",
    "mode": "NULLABLE"
  },
  {
    "type": "STRING",
    "name": "Product",
    "mode": "NULLABLE"
  }
  ]
}