Data Engineering Fundamentals 2

Question 1

What is the primary difference between ETL and ELT?

Accepted Answer

ETL transforms data before loading into the target; ELT loads raw data first then transforms inside the target

Answer

ETL is only for streaming data while ELT is only for batch

Answer

ETL requires a data lake while ELT requires a relational database

Answer

There is no difference; the terms are interchangeable

Question 2

Which file format is columnar and optimized for analytical query performance?

Accepted Answer

Parquet

Answer

CSV

Answer

JSON

Answer

XML

Question 3

What does idempotency mean for a data pipeline task?

Accepted Answer

Running the task multiple times produces the same result as running it once

Answer

The task can only run once per day

Answer

The task automatically retries on failure

Answer

The task processes data in parallel

Question 4

In a star schema, the central table that holds measurable business events is called the:

Accepted Answer

Fact table

Answer

Dimension table

Answer

Bridge table

Answer

Lookup table

Question 5

Which tool is most commonly used to orchestrate and schedule batch data workflows as DAGs?

Accepted Answer

Apache Airflow

Answer

Apache Kafka

Answer

Redis

Answer

Nginx

Question 6

What is the main purpose of data partitioning in a large table?

Accepted Answer

To improve query performance and manageability by dividing data into segments

Answer

To encrypt sensitive columns

Answer

To normalize the schema

Answer

To enforce foreign key constraints

Question 7

A schema-on-read approach is most characteristic of which storage system?

Accepted Answer

A data lake

Answer

A traditional relational data warehouse

Answer

A normalized OLTP database

Answer

A stored procedure