Databricks Data Engineer Professional Question 67
Select 3You are working with a Delta Lake table in Databricks and need to update multiple records based on specific conditions using a Type 1 update strategy (overwrite existing values without maintaining history). Which of the following approaches are valid for achieving this?
- A
Use the Delta Lake
MERGE INTOstatement with a matching condition for updates. - B
Use the Spark SQL
INSERT OVERWRITEstatement to replace the entire table with the updated records. - C
Utilize the Delta Lake
UPDATEstatement with a filtering condition that identifies the records to be updated. - D
Perform an upsert operation by unioning the updated records with the non-matching records, then writing back to the Delta table.
- E
Use the
DELETEstatement in Delta Lake to remove existing records, followed by anINSERTstatement to add the updated records.
Show answer and explanation
Correct answers: A, C, D
Explanation
For Type 1 updates, the goal is to update existing records without maintaining history. The MERGE INTO statement, the UPDATE statement, and the upsert strategy using unions are all valid approaches for achieving this. INSERT OVERWRITE and DELETE + INSERT are either inefficient or not aligned with the Type 1 update strategy, as they replace or remove data unnecessarily.
- A. Correct.
Correct. The
MERGE INTOstatement is specifically designed for upserts and can handle updates to multiple records based on a matching condition, making it a common choice for Type 1 updates. - B. Incorrect.
Incorrect. The
INSERT OVERWRITEstatement replaces the entire table, which is inefficient and not specific to updating only matching records. This approach is not ideal for Type 1 updates. - C. Correct.
Correct. The
UPDATEstatement allows you to update specific records in a Delta table by providing a filtering condition. This is another valid strategy for Type 1 updates. - D. Correct.
Correct. By using a union of updated and non-matching records, you can effectively perform an upsert operation. This strategy is valid for Type 1 updates when done correctly.
- E. Incorrect.
Incorrect. The
DELETEfollowed byINSERTapproach is inefficient and typically used in non-Type 1 scenarios. It does not align with standard Type 1 update strategies.