LFC Data Management 2

Question 1

Which Delta Lake feature enables you to travel back to a previous version of a table to correct a data error?

Accepted Answer

Time Travel

Answer

Delta Lake's Time Travel feature allows querying or restoring a table to any prior snapshot using a version number or timestamp.

Question 2

In a lakehouse, what does the term 'schema enforcement' primarily prevent?

Accepted Answer

Data that doesn't match the defined schema from being inserted

Answer

Schema enforcement (schema validation) rejects writes whose column types or names don't conform to the table's declared schema.

Question 3

What is the primary purpose of the Delta Lake transaction log (_delta_log)?

Accepted Answer

Record every change to a Delta table as an ordered series of atomic commits

Answer

The _delta_log directory holds JSON and Parquet checkpoint files that form an ordered audit trail of all table operations.

Question 4

A data engineer wants to merge new customer records into an existing Delta table, updating existing rows and inserting new ones. Which SQL operation should they use?

Accepted Answer

MERGE INTO

Answer

MERGE INTO (upsert) matches source rows to target rows on a key and performs combined insert/update/delete actions in one atomic operation.

Question 5

Which data management practice in the lakehouse architecture keeps old, unreferenced data files from accumulating and consuming storage?

Accepted Answer

VACUUM

Answer

The VACUUM command removes data files no longer referenced by the Delta transaction log and older than the retention threshold.

(LFC) Lakehouse Fundamentals Certification Practice Test

(LFC) Lakehouse Fundamentals Certification Practice Test

LFC Data Management 2