After understanding how data pipelines move information, the next logical step is to consider where that data resides. Storing data effectively is fundamental to any data engineering task, as the choice of storage impacts accessibility, performance, and cost.

This chapter examines the core principles of data storage relevant to data engineers. You will learn about different storage paradigms and when to use them:

• Relational Databases: The basics of structured data storage and interaction using SQL.
• NoSQL Databases: An overview of alternative database types for different data models.
• File Systems: Concepts behind distributed file storage often used in big data scenarios.
• Object Storage: Understanding scalable storage for unstructured or semi-structured data.
• Data Formats: Recognizing common formats like CSV, JSON, and Parquet and their use cases.

By the end of this chapter, you will have a foundational understanding of the primary data storage options available and the factors involved in selecting the appropriate solution for a given task. We will also practice setting up a basic database table.