Databricks-DE-Pro Data Modelling Practice Question
A data engineer is building a Silver layer table that combines data from multiple Bronze tables. The engineer wants to ensure that the Silver table only contains the most recent version of each record based on a 'last_updated' timestamp. Which Delta Lake operation should be used to achieve this?
⚠ Common exam trap
The trap here is thinking that INSERT OVERWRITE is sufficient for incremental updates, but it actually replaces all data and does not handle record-level versioning.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
MERGE INTO with a condition that updates when the source timestamp is greater
MERGE INTO is the correct operation because it can conditionally update existing rows with newer timestamps and insert new rows, ensuring the Silver table contains only the latest version of each record. INSERT OVERWRITE, DELETE+INSERT, and time travel do not provide the same atomic upsert capability and would either be inefficient or incorrect for this scenario.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
DELETE then INSERT the new records
Why it's wrong here
Deleting and re-inserting is non-atomic and can lead to temporary data loss or inconsistencies for concurrent readers. It also does not guarantee that only the latest record is kept if multiple versions exist. MERGE is preferred because it handles both updates and inserts in a single transaction.
- ✗
Use Delta Lake time travel to revert to a previous version
Why it's wrong here
Time travel is for querying historical snapshots, not for maintaining a current view. Reverting to a previous version would discard newer data, which is the opposite of what is needed. It does not help in deduplicating records based on timestamps; it is a read feature, not a write operation.
- ✗
INSERT OVERWRITE with the entire dataset
Why it's wrong here
INSERT OVERWRITE replaces the entire table or partition, which is inefficient for incremental updates and loses history. It does not handle record-level deduplication based on timestamps. This approach would require reprocessing all data and is not suitable for maintaining a current view with minimal compute.
- ✓
MERGE INTO with a condition that updates when the source timestamp is greater
Why this is correct
MERGE INTO allows you to update existing records when the incoming data has a newer timestamp and insert new records when they don't exist. This ensures that the Silver table always reflects the latest version. It is the standard way to upsert data in Delta Lake while maintaining ACID compliance.
About these practice questions
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Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Databricks exam blueprint
This Databricks-DE-Pro practice question is part of Courseiva's free Databricks certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the Databricks-DE-Pro exam.