BigQueryGetDataOperator

Google

Fetches the data from a BigQuery table (alternatively fetch data for selected columns) and returns data in a python list. The number of elements in the returned list will be equal to the number of rows fetched. Each element in the list will again be a list where element would represent the columns values for that row.

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Last Updated: May. 4, 2021

Access Instructions

Install the Google provider package into your Airflow environment.

Import the module into your DAG file and instantiate it with your desired params.

Parameters

dataset_idstrThe dataset ID of the requested table. (templated)
table_idstrThe table ID of the requested table. (templated)
max_resultsintThe maximum number of records (rows) to be fetched from the table. (templated)
selected_fieldsstrList of fields to return (comma-separated). If unspecified, all fields are returned.
gcp_conn_idstr(Optional) The connection ID used to connect to Google Cloud.
bigquery_conn_idstr(Deprecated) The connection ID used to connect to Google Cloud. This parameter has been deprecated. You should pass the gcp_conn_id parameter instead.
delegate_tostrThe account to impersonate using domain-wide delegation of authority, if any. For this to work, the service account making the request must have domain-wide delegation enabled.
locationstrThe location used for the operation.
impersonation_chainUnion[str, Sequence[str]]Optional service account to impersonate using short-term credentials, or chained list of accounts required to get the access_token of the last account in the list, which will be impersonated in the request. If set as a string, the account must grant the originating account the Service Account Token Creator IAM role. If set as a sequence, the identities from the list must grant Service Account Token Creator IAM role to the directly preceding identity, with first account from the list granting this role to the originating account (templated).

Documentation

Fetches the data from a BigQuery table (alternatively fetch data for selected columns) and returns data in a python list. The number of elements in the returned list will be equal to the number of rows fetched. Each element in the list will again be a list where element would represent the columns values for that row.

Example Result: [['Tony', '10'], ['Mike', '20'], ['Steve', '15']]

See also

For more information on how to use this operator, take a look at the guide: Fetch data from table

Note

If you pass fields to selected_fields which are in different order than the order of columns already in BQ table, the data will still be in the order of BQ table. For example if the BQ table has 3 columns as [A,B,C] and you pass ‘B,A’ in the selected_fields the data would still be of the form 'A,B'.

Example:

get_data = BigQueryGetDataOperator(
task_id='get_data_from_bq',
dataset_id='test_dataset',
table_id='Transaction_partitions',
max_results=100,
selected_fields='DATE',
gcp_conn_id='airflow-conn-id'
)

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