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

Data modeling is a critical step in building effective Power BI reports. It shows how data is structured, connected, and used to generate understanding. A well-designed model improves performance and ensures accuracy, while a poor one can lead to slow dashboards and incorrect results. This article explains data modeling in Power BI, covering SQL joins, relationships, schemas, and how to implement each step in practice. Data Modeling Data modeling is the process of organizing data into tables and showing how those tables relate to one another. This happens after data is imported and transformed. Purpose of data modelling: Efficient calculations Structure of data improve efficiency and clarity SQL joins What are joins? They are used to combine rows from two or more tables based on a related column. 1.Inner join Returns only matching rows from both tables. 2.LEFT JOIN (LEFT OUTER) Returns all rows from the left table and matching rows from the right. 3.RIGHT JOIN (RIGHT OUTER) Returns all