Week 4/33: Data Modelling for Data Engineering Interviews (Part #1)

Week 4 of 33-Week Data Engineering Interview Guide

Data modelling is essential in Data Engineering as it defines how data is organised and connected within a system. It's a common focus in interviews, reflecting its importance in creating efficient, scalable, and reliable pipelines and databases. Strong data modelling skills showcase your ability to solve real-world data challenges.

Additionally, there are roles specifically called Data Modelers that intersect with Data Engineering. As a Data Engineer, you may come across these specialised roles, which focus more deeply on designing and optimising data models. These roles highlight the importance of data modelling in the broader data engineering landscape.

For a Data Engineering interview, the question patterns usually follow three common types:

1. The interviewer presents a scenario and asks you to design an ER diagram, Dimensional Model, or similar, based on the given requirements.

2. They provide an existing ER diagram and ask you to normalise or denormalise it.

3. They ask general questions to assess your overall understanding of data modelling concepts and best practices.

In this post, we’ll start with the fundamentals and then work through real examples, helping you become familiar with the different types of data modelling questions.

What we will cover :

• What is data modelling?

• What is a data model?

• Types of data models

• OLTP vs. OLAP

• ER Diagrams and ER Models

• Step-by-step guide to solving Amazon’s data modeling interview question

We will also provide real interview questions from Microsoft, Uber and Meta.

For the full plan for the series, check out:

Week 0/32 - A Comprehensive Data Engineering Interview Preparation Guide

Note: We originally planned to cover this topic in two posts but to fully explore the concepts and address all interview-relevant aspects, we've extended the Data Modeling series to three posts.

By the end of the series, you'll have a solid understanding of data modelling basics and be confident in handling interview questions.

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What is Data Modeling?

Definition

Data modelling is the process of creating a visual representation of data and its relationships within a system.