11.1 Why Data Modelling Matters
A data model is the set of tables, the relationships between them and the calculations on top. A good model makes DAX simple, reports fast and numbers correct. A poor model (one giant flat table, or many-to-many relationships everywhere) causes slow reports and wrong totals. In interviews, strong modelling knowledge is what separates a report maker from a Power BI developer.
Ravindra Bagale's Tip
Mitrano, khup students build every visual on one big flat table exported from Excel and then struggle with totals and slow reports. Split it into a fact table and dimensions early. A good model makes DAX simple, and a bad model makes every measure a fight. Bilkul visru naka.