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

Data modeling is how you structure your tables so Power BI understands how they connect. Get it right, and your reports are fast, accurate, and easy to maintain. Get it wrong, and you'll spend hours debugging. SQL Joins in Power Query Joins combine tables into one and happen in Power Query (Transform Data). Use them when you need a flat table. Sample tables: CustomerID CustomerName 1 John Smith 2 Sarah Jones 3 Mike Brown 4 Emma Wilson OrderID CustomerID Amount 101 1 100 102 1 150 103 2 200 104 5 75 INNER JOIN Returns only matching rows from both tables. Result: Customers 1 and 2 with their orders. LEFT JOIN Returns all rows from left table, matching from right. Result: All customers; customers 3 and 4 show NULL for orders. RIGHT JOIN Returns all rows from right table, matching from left. Result: All orders; order 104 shows NULL for customer. FULL OUTER JOIN Returns all rows from both tables. Result: All customers and all orders; NULLs where no match. LEFT ANTI JOIN Returns rows from le