Databricks Certified Data Engineer Professional · Free Practice Question Medium
Question 8
The data engineering team has the following query for processing customers’ requests to be forgotten:
- DELETE FROM customers
- WHERE customer_id IN
- (SELECT customer_id FROM delete_requests)
Which statement describes the results of executing this query ?
-
A
The identified records will be deleted from the customers tables, and their associated data files will be permanently purged from the table directory.
-
B
The identified will be deleted from the both customers and delete_requests tables, and their associated data files will be permanently purged from the tables directories.
-
C
The identified records will be deleted from the customers table, but they will still be accessible in the table history until a VACUUM command is run.
-
D
The identified records will be deleted from both customers and delete_requests tables, but they will still be accessible in the table history until VACUUM commands are run.
-
E
The identified records will be deleted from the customers tables, but they will still be accessible in the table history until updating the status of the requests in the delete_requests table
Reveal correct answer
Correct answer: C
Explanation
Delete requests, also known as requests to be forgotten, require deleting user data that represent Personally Identifiable Information or PII, such as the name and the email of the user.
Because of how Delta Lake tables time travel are implemented, deleted values are still present in older versions of the data. Remember, deleting data does not delete the data files from the table directory. Instead, it creates a copy of the affected files without these deleted records. So, to fully commit these deletes, you need to run VACUUM commands on the customers table.
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