Practice Test 3 | Google Cloud Certified Professional Data Engineer | Dumps | Mock Test
You have raw data related to retail chain products and purchase records, stored as CSV files in Google Storage. Analytics team wants to use the data for extracting useful statistics for management. They want to run a simple ETL pipeline which analytics will use SQL to do the required transformation and table joins. What is the best approach to achieve this?
A. Create external tables on data using BigQuery. Run transformation queries on data then load the output to an internal BigQuery table for reporting and visualization.
B. Create external tables on data using BigQuery. Run transformation queries on data then load the output to BigTable for reporting and visualization.
C. Import the data from Google Storage to BigQuery. Run transformation queries on data and insert the transformed records to a different BigQuery table.
D. Import the data from Google Storage to BigQuery. Run transformation queries on data and export the data to Google Storage. Launch Dataproc cluster and use Hive to query the transformed data.
Correct Answer: A
An external data source (also known as a federated data source) is a data source that allows you to query directly even though the data is not stored in BigQuery. Instead of loading or streaming the data, you create a table that references the external data source.
Querying an external data source using a temporary table is useful for one-time, ad-hoc queries over external data, or for extract, transform, and load (ETL) processes.
In summary, using external tables in BigQuery is useful for such cases:
- Perform ETL operations on data.
- Frequently changed data.
- Data is being ingested periodically.
Option B is incorrect because BigTable isn’t a practical (and cheap) approach to report and visualize data.
Options C and D are incorrect: Based on Google’s best practices, using external tables for ETL is better than loading data to BigQuery.
Source(s):
BigQuery external tables:
https://cloud.google.com/bigquery/external-data-sources
BigQuery – Define external tables:
Comments are closed, but trackbacks and pingbacks are open.