Databricks Certified Data Engineer Associate — Question 88

In a healthcare provider organization using Delta Lake to store electronic health records (EHRs), a data analyst needs to analyze a snapshot of the patient_records table from two weeks ago before some recent data corrections were applied.

What approach should the Data Engineer take to allow the analyst to query that specific prior version?

Answer options

• A. Truncate the table to remove all data, then reload the data from two weeks ago into the truncated table for the analyst to query.
• B. Identify the version number corresponding to two weeks ago from the Delta transaction log, share that version number with the analyst to query using VERSION AS OF syntax, or export that version to a new Delta table for the analyst to query.
• C. Restore the table to the version from two weeks ago using the RESTORE command, and have the analyst query the restored table.
• D. Use the VACUUM command to remove all versions of the table older than two weeks, then the analyst can query the remaining version.

Correct answer: B

Explanation

The correct approach is to identify the version number from the Delta transaction log that reflects the state of the table two weeks ago and share it with the analyst. This allows the analyst to use the VERSION AS OF syntax to query that specific version without altering the current table state. The other options either disrupt the existing data or do not provide a straightforward way to access historical data without loss or complications.