Data Engineering Fundamentals 3

Question 1

What is a slowly changing dimension (SCD) Type 2 designed to do?

Accepted Answer

Preserve full history by adding new rows for changed attributes

Answer

SCD Type 2 keeps historical changes by inserting a new row each time a tracked attribute changes.

Question 2

Which guarantee does 'exactly-once' processing provide in a streaming system?

Accepted Answer

Each record is processed once with no duplicates or loss

Answer

Exactly-once semantics ensure every record affects the result a single time, even across failures and retries.

Question 3

What is the role of a message broker like Apache Kafka in a data architecture?

Accepted Answer

It decouples producers and consumers by buffering streams of events

Answer

Kafka acts as a durable, scalable buffer that decouples data producers from consumers via topic-based event streams.

Question 4

Which normalization concept aims to reduce data redundancy in a relational design?

Accepted Answer

Normalization to higher normal forms

Answer

Normalization organizes tables to minimize redundancy and dependency by progressing through normal forms.

Question 5

What does 'backfilling' a pipeline mean?

Accepted Answer

Processing past time periods that were missed or need reprocessing

Answer

Backfilling runs a pipeline over historical date ranges to populate or correct data that was missing or wrong.

Data Engineering Practice Test