Is Delta Lake deeply tested in Professional Data Engineer Exam?

[tonybenzu99]

I wanted to ask people who have already taken the Databricks Certified Professional Data Engineer exam whether Delta Lake is tested in depth or not. While preparing, I’m currently using the Databricks Certified Professional Data Engineer sample questions from Pass4Future, and I’ve noticed that Delta Lake topics like MERGE operations, OPTIMIZE and Z-ORDER, schema evolution, time travel, and ACID transactions appear quite frequently. This makes me wonder if the real exam focuses heavily on practical, scenario-based Delta Lake questions or if the actual test is more high-level and conceptual. I’d really appreciate hearing from anyone who has real exam experience and can confirm how deep the Delta Lake coverage actually is.

[szymon_dybczak]

Hi @tonybenzu99 ,

You can expect question related to Delta Lake. In my case there were question about delta related to optimization, cloning feature etc.

You can check the current exam objectives here. Check what will be checked at each section of exam and prepare accordingly. I recommeded Derar Alhussein course with exam question. It was really helpful when I was approaching exam.

Databricks Certified Data Engineer Professional Exam Guide - November 30, 2025

Databricks Certified Data Engineer Professional Exam Guide - November 30, 2025

[lucafredo]

Yes, Delta Lake concepts are an important part of the Databricks Professional Data Engineer exam, but they aren’t tested in extreme depth compared to core Spark transformations and data pipeline design. The exam mainly focuses on practical understanding, for example:
- How to create and manage Delta tables
- Using ACID transactions and time travel
- Optimizing data with Z-Ordering and compaction
- Handling schema evolution and merges
You don’t need to memorize every internal detail of Delta Lake, but you should be comfortable applying it in real-world pipelines and understanding when and why you would use Delta features versus raw Parquet or other formats.
A good approach is to practice with sample Delta Lake pipelines in Databricks and review the official Delta Lake docs. Hands-on experience helps more than just reading theory, especially since many exam questions are scenario-based.
Hope this helps clarify the focus for Delta Lake in the exam!