Understanding Data Modeling in Power BI: Joins, Relationships, and Schemas Explained.

Two weeks ago I had no idea what Power BI is, what data modeling means, or why people keep talking about joins and relationships. Everything sounded complicated and honestly, a bit overwhelming. But as I started learning step by step, I realized these concepts are actually very logical and easy to understand when explained in a simple way. Let us start with joins, because that is where most people begin when working with data. When working with data, we often have multiple tables that need to be connected. For example, you might have a customers table and a sales table. The customers table contains details like customer names, while the sales table contains transactions such as what was bought and how much was spent. These tables are connected using a common column like Customer ID. This is where joins come in. A join helps us combine data from two tables based on a common column. But not all joins behave the same way. Each type of join answers a different kind of question. A left join