Upon scrutinizing the schema reflection for Big Query, I am able to discern the dataset lists and glean information about the columns to a certain extent. Although it's not a mandatory requirement, I have the capability to establish primary and foreign keys on tables. However, when I attempt to retrieve this information using an inspector, the following code doesn't yield the expected results:

from sqlalchemy import inspect, create_engine
engine = create_engine('...')
inspector = inspect(engine)
primary_key = inspector.get_pk_constraint("table_name")  # returns empty
foreign_keys = inspector.get_foreign_keys("table_name")  # returns empty

Given this situation, I am wondering if there's an alternative method to extract this data without having to resort to SQL Queries on INFORMATION_SCHEMA?