Databricks Data Engineer Associate Question 105
Select 3A data engineering team is working with a new set of tables sourced from an external data warehouse. They want to confirm whether these tables are Delta Lake tables before performing Delta-specific operations. Which of the following methods can be used to identify that the tables are NOT Delta Lake tables?
- A
Query the table properties and check if 'delta' is listed as the table provider.
- B
Inspect the storage location and verify the presence of '_delta_log' folder.
- C
Query the table schema and check for a 'delta_version' column.
- D
Run DESCRIBE DETAIL on the table and check if the format is listed as 'delta'.
- E
Attempt to perform a MERGE operation on the table.
Show answer and explanation
Correct answers: A, B, D
Explanation
Delta Lake tables have specific characteristics, such as 'delta' as the table provider, the presence of a '_delta_log' folder in the storage location, and the format being listed as 'delta' in DESCRIBE DETAIL output. These are reliable methods to verify whether a table is a Delta Lake table or not. Schema inspection or testing specific operations like MERGE are not reliable methods for this purpose.
- A. Correct.
Correct: Querying the table properties and checking if 'delta' is listed as the table provider is a valid method to determine if the table is a Delta Lake table. If the table is NOT Delta, the provider will not be 'delta'.
- B. Correct.
Correct: Inspecting the storage location for the presence of the '_delta_log' folder is a reliable way to check if the table is a Delta Lake table. If the '_delta_log' folder is absent, the table is not a Delta Lake table.
- C. Incorrect.
Incorrect: The presence of a 'delta_version' column in the schema is not a valid method to identify Delta tables. Delta Lake tables do not have a special 'delta_version' column by default.
- D. Correct.
Correct: Running DESCRIBE DETAIL on the table and checking the format field is a valid method to confirm if the table uses Delta Lake. If the format is not listed as 'delta', the table is not a Delta Lake table.
- E. Incorrect.
Incorrect: Attempting a MERGE operation is not a recommended method to identify Delta tables. While a failure may indicate the table is not Delta, the error could also be due to other reasons such as unsupported operations on the table.