Power BI Data Modelling Explained: Star Schema, Relationships, and Table Types

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Power BI reports rely on well-structured data models that clean and logically connect data from multiple sources for fast performance and accurate DAX calculations. Tables can be organised as a single flat table, a star schema, or a snowflake schema, with the star schema considered the optimal approach due to its balance of speed and clarity. In a star schema, Fact tables store numerical business events such as sales transactions, while Dimension tables hold descriptive details like customer names and product categories. Tables are linked through relationships — most commonly one-to-many — using unique primary keys in dimension tables and repeating foreign keys in fact tables. Without properly defined relationships, filters and visuals on a dashboard will fail to interact correctly, leading to inaccurate reporting.

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Power BI Data Modelling Explained: Flat Tables vs Star Schema and Relationships

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