Databricks Machine Learning Professional exam dumps

Databricks Machine Learning Professional practice question 15 of 280

Databricks Certified Machine Learning Professional. Professional level, Databricks. Free question with the correct answer and a full explanation.

Databricks Machine Learning Professional Question 15

Select 3

A data science team maintains a Delta table named 'sales_data' to track transaction records. The team recently made several updates to the table, but now they want to analyze the table's history to identify when specific changes were made and revert to a version from three updates ago. Which of the following steps should they take to achieve this?

  1. A

    Use the DESCRIBE HISTORY command to view the Delta table's transaction history.

  2. B

    Identify the version number of the desired table state from the transaction history.

  3. C

    Use the RESTORE TABLE command to revert the Delta table to the desired version.

  4. D

    Load the previous table version using the versionAsOf option in a DataFrame read operation.

  5. E

    Use the DROP TABLE command to remove the latest changes and revert to the desired version.

Show answer and explanation

Correct answers: A, B, D

Explanation

To analyze changes and revert to a previous version of a Delta table, the data science team should first use the DESCRIBE HISTORY command to inspect the table's transaction history and find the desired version number. Once identified, they can use the versionAsOf option to load the specific version into a DataFrame for analysis without overwriting the current table. This approach ensures non-destructive exploration of past table states.

  • A. Correct.

    Correct: The DESCRIBE HISTORY command provides a detailed history of all changes made to the Delta table, including timestamps, operation types, and version numbers.

  • B. Correct.

    Correct: Identifying the version number from the history is necessary to either restore or load a specific version of the Delta table.

  • C. Incorrect.

    Incorrect: The RESTORE TABLE command is not currently supported in Delta Lake for reverting to a previous version. Instead, you should use other methods, such as versionAsOf or overwriting the table with older data.

  • D. Correct.

    Correct: The versionAsOf option allows you to load a specific version of a Delta table into a DataFrame for analysis or further processing.

  • E. Incorrect.

    Incorrect: The DROP TABLE command permanently deletes the table and its metadata, which is not a valid approach for reverting to a previous version in Delta Lake.

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