Databricks Certified Data Engineer Professional — Question 199

What is true for Delta Lake?

Answer options

• A. Views in the Lakehouse maintain a valid cache of the most recent versions of source tables at all times.
• B. Primary and foreign key constraints can be leveraged to ensure duplicate values are never entered into a dimension table.
• C. Delta Lake automatically collects statistics on the first 32 columns of each table which are leveraged in data skipping based on query filters.
• D. Z-order can only be applied to numeric values stored in Delta Lake tables.

Correct answer: C

Explanation

Option C is correct because Delta Lake indeed collects statistics on the first 32 columns of each table to enhance query performance through data skipping. Options A and B are misleading as they do not accurately represent Delta Lake's functionality regarding views and constraints. Option D is incorrect because Z-order can be applied to various types of data, not just numeric values.