Databricks Data Engineer Associate Question 328
Single answerA data engineering team is working on a Delta Lake table in Databricks. They need to update the contents of the table with new data. However, they want to ensure the schema of the table is updated if necessary and any existing data in the table is overwritten. Which approach should they use?
- A
Use CREATE OR REPLACE TABLE with the new data.
- B
Use INSERT OVERWRITE to replace the existing data in the table.
- C
Use CREATE OR REPLACE TABLE only if schema evolution is not required.
- D
Use INSERT OVERWRITE only if the table schema matches exactly with the new data.
Show answer and explanation
Correct answer: A
Explanation
CREATE OR REPLACE TABLE is the best choice when both schema updates and data replacement are needed. It drops the existing table and creates a new one with the provided data and schema. In contrast, INSERT OVERWRITE only replaces the data in an existing table and requires the schema to already match.
- A. Correct.
This is correct because CREATE OR REPLACE TABLE replaces the table’s existing contents and supports schema updates (schema evolution).
- B. Incorrect.
This is incorrect because INSERT OVERWRITE replaces the data but does not update the table schema. It requires the new data to match the existing schema exactly.
- C. Incorrect.
This is incorrect because CREATE OR REPLACE TABLE inherently supports schema evolution without requiring additional conditions.
- D. Incorrect.
This is incorrect because INSERT OVERWRITE does not support schema updates and works only if the schemas match exactly.