Data frequently originates from or is stored in relational database systems. Understanding how these systems organize information is a prerequisite for effective data retrieval and analysis in data science. This first chapter lays the groundwork.

We will cover the structure of relational databases, including tables, columns, rows, and fundamental data types. Following this, we introduce Structured Query Language (SQL), the primary tool for communicating with these databases. By the end of this chapter, you will understand the basic terminology and the purpose of SQL in the context of data access. Optional guidance on setting up a practice environment is also included.