python bigquery获取外部表元数据

Question

I want to get the external meta data of a table created in bigquery. The table was created like this:

table_ref = self._client.dataset('test').table('test')
table = bigquery.Table(table_ref)

self._extconfig = bigquery.ExternalConfig('AVRO')
self._extconfig.autodetect = True
self._extconfig.source_uris = ['gs://someproject/bucket/dir/file*.avro']
table.external_data_configuration = self._extconfig
self._client.create_table(table)

Now i want to access the meta data stored in external_data_configuration' like this:

dataset = self._client.dataset('test')
table_ref = dataset.table('test')
table = bigquery.Table(table_ref)
print(table.table_id)
print(table.path)
print(table.table_type)
print(table.external_data_configuration)

But all i receive is None for table_type, where i would expect 'AVRO' and also None for external_data_configuration.

Is there a way to get the external_data_configuration, especially the source_uris for external tables?

Answer 1

Try this instead:

dataset = self._client.dataset('test')
table_ref = dataset.table('test')
table = self._client.get_table(table_ref)
print(table.external_data_configuration.source_uris)

The get_table will fetch all the information of the table into the table variable.