Data Engineers' primary job is to ingest data from various sources into a data lake. This data should be organized in proper formats, processed desirably, and stored safely and in accordance with provided storage capacity and hardware architecture. Data engineers are in charge of developing and maintaining data infrastructure and applications and setting up data warehouses and pipelines. In the following Figure, you can see some of the most usual tasks in any data engineer's daily life.

As you can see, proficiency in work with multiple technologies is required. But don't worry. In the following paragraphs, we'll help you understand what you need to know to be a competitive data engineer candidate and what fundamental topics you should pay attention to for an interview.