Python BigQuery API - 获取 table 架构

Question

我正在尝试从 bigquery 获取模式 table。给定一个示例代码

from google.cloud import bigquery
from google.cloud import storage

client =  bigquery.Client.from_service_account_json('service_account.json')

def test_extract_schema(client): 
    project = 'bigquery-public-data'
    dataset_id = 'samples'
    table_id = 'shakespeare'

    dataset_ref = client.dataset(dataset_id, project=project)
    table_ref = dataset_ref.table(table_id)
    table = client.get_table(table_ref)  # API Request

    # View table properties
    print(table.schema)

if __name__ == '__main__':
    test_extract_schema(client)

返回值如下：

[SchemaField('word', 'STRING', 'REQUIRED', 'A single unique word (where whitespace is the delimiter) extracted from a corpus.', ()), SchemaField('word_count', 'INTEGER', 'REQUIRED', 'The number of times this word appears in this corpus.', ()), SchemaField('corpus', 'STRING', 'REQUIRED', 'The work from which this word was extracted.', ()), SchemaField('corpus_date', 'INTEGER', 'REQUIRED', 'The year in which this corpus was published.', ())]

我尝试仅以

格式捕获架构

'word' 'STRING','word_count' INTEGER'

有没有办法使用 API 调用或任何其他方法来获取此信息？

Answer 1

您始终可以获取 table.schema 变量并对其进行迭代，因为 table 是由 SchemaField 个值组成的列表：

result = ["{0} {1}".format(schema.name,schema.field_type) for schema in table.schema]

同一数据集的结果 table:

['word STRING', 'word_count INTEGER', 'corpus STRING', 'corpus_date INTEGER']

Answer 2

here、schema已过期。

Answer 3

另一种方法是，在您拥有客户端和 table 实例之后，执行如下操作：

import io
f = io.StringIO("")
client.schema_to_json(table.schema, f)
print(f.getvalue())

Python BigQuery API - 获取 table 架构

Python BigQuery API - get table schema

python-3.x

google-bigquery

google-cloud-datastore

google-cloud-platform