> ## Documentation Index
> Fetch the complete documentation index at: https://docs.activeviam.com/llms.txt
> Use this file to discover all available pages before exploring further.

# ConnectionConfig

<span id="atoti_directquery_bigquery.ConnectionConfig" />

> atoti\_directquery\_bigquery.ConnectionConfig(<br />
>     \*,<br />
>     *time\_travel*: [bool](https://docs.python.org/3/library/functions.html#bool) = `True`,<br />
>     *cache*: [bool](https://docs.python.org/3/library/functions.html#bool) = `True`,<br />
>     *auto\_multi\_column\_array\_conversion*: [AutoMultiColumnArrayConversion](./atoti.directquery.array_conversion.AutoMultiColumnArrayConversion#atoti.AutoMultiColumnArrayConversion) | [None](https://docs.python.org/3/library/constants.html#None) = `None`,<br />
>     *column\_clustered\_queries*: 'all' | 'feeding' = `'feeding'`,<br />
>     *feeding\_query\_timeout*: Duration = `datetime.timedelta(seconds=3600)`,<br />
>     *lookup\_mode*: 'allow' | 'warn' | 'deny' = `'warn'`,<br />
>     *max\_sub\_queries*: Annotated\[[int](https://docs.python.org/3/library/functions.html#int), Field(gt=0)] = `500`,<br />
>     *query\_timeout*: Duration = `datetime.timedelta(seconds=300)`,<br />
>     *credentials*: [Path](https://docs.python.org/3/library/pathlib.html#pathlib.Path) | [None](https://docs.python.org/3/library/constants.html#None) = `None`,<br />
> )

Config to connect to a BigQuery database.

```pycon theme={"languages":{"custom":["/engine/python-sdk/0.9/languages/pycon.tmLanguage.json"]}}
>>> from atoti_directquery_bigquery import ConnectionConfig
>>> connection_config = ConnectionConfig()
>>> external_database = session.connect_to_external_database(connection_config)
```

### Attributes

<h4 id="atoti_directquery_bigquery.ConnectionConfig.credentials">
  *credentials*
</h4>

The path to the [BigQuery credentials file](https://cloud.google.com/docs/authentication/getting-started#setting_the_environment_variable).

If `None`, the [application default credentials](https://cloud.google.com/java/docs/reference/google-auth-library/latest/com.google.auth.oauth2.GoogleCredentials#com_google_auth_oauth2_GoogleCredentials_getApplicationDefault__) will be used.

<h4 id="atoti_directquery_bigquery.ConnectionConfig.auto_multi_column_array_conversion">
  *auto\_multi\_column\_array\_conversion*
</h4>

When not `None`, multi-column array conversion will be performed automatically.

<h4 id="atoti_directquery_bigquery.ConnectionConfig.cache">
  *cache*
</h4>

Whether to look for query results in the external database query cache.

<h4 id="atoti_directquery_bigquery.ConnectionConfig.column_clustered_queries">
  *column\_clustered\_queries*
</h4>

Control which queries will use clustering columns.

<h4 id="atoti_directquery_bigquery.ConnectionConfig.feeding_query_timeout">
  *feeding\_query\_timeout*
</h4>

Timeout for queries performed on the external database during feeding phases.

The feeding phases are:

* the initial load to feed [`aggregate_providers`](./atoti.Cube.aggregate_providers#atoti.Cube.aggregate_providers) and [`hierarchies`](./atoti.Cube.hierarchies#atoti.Cube.hierarchies);
* the refresh operations.

<h4 id="atoti_directquery_bigquery.ConnectionConfig.lookup_mode">
  *lookup\_mode*
</h4>

Whether lookup queries on the external database are allowed.

Lookup can be very slow and expensive as the database may not enforce primary keys.

<h4 id="atoti_directquery_bigquery.ConnectionConfig.max_sub_queries">
  *max\_sub\_queries*
</h4>

Maximum number of sub queries performed when splitting a query into multi-step queries.

<h4 id="atoti_directquery_bigquery.ConnectionConfig.query_timeout">
  *query\_timeout*
</h4>

Timeout for queries performed on the external database outside feeding phases.

<h4 id="atoti_directquery_bigquery.ConnectionConfig.time_travel">
  *time\_travel*
</h4>

Whether to use time travel in queries.