Practice Test 1 | Google Cloud Certified Professional Data Engineer | Dumps | Mock Test
Analytics team receives data from different data sources stored in Google Storage. The team wants to query the data for required ETL operations which they will fully take care of using SQL. They want your advice on what is the best approach recommended by Google to do it. What would you suggest?
A. Batch load the data from Google Storage into BigQuery using its batch API, run cleansing and transformation queries on data and insert the transformed rows to another BigQuery table.
B. Batch load the data from Google Storage into BigQuery using its batch API, run cleansing and transformation queries on data and export the data to Google Storage. Launch Dataproc cluster and use Hive to query the transformed data.
C. Create external tables on data using BigQuery, apply the cleansing and transformation queries on data then load the output to an internal BigQuery table for reporting and visualization.
D. Create external tables on data using BigQuery, apply the cleansing and transformation queries on data then load the output to BigTable for reporting and visualization.
Answer: C.
An external data source (also known as a federated data source) is a data source that you can 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:
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- Perform ETL operations on data.
- Frequently changed data.
- Data is being ingested periodically.
Answer C is the correct answer based on above explanation and using BigQuery for reporting and visualization is a better approach.
Answer D is incorrect because BigTable isn’t a practical (and cheap) approach to report and visualize data.
Answers A & B 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: https://cloud.google.com/bigquery/external-table-definition
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