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

Data modelling in Power BI organizes tables and defines relationships so analysis is efficient and accurate.

Power Query performs physical joins via Merge Queries using join types like INNER, LEFT, RIGHT, FULL, and ANTI joins.

Power BI relationships connect tables logically with cardinalities such as One-to-Many, Many-to-Many, and One-to-One and have single or both cross-filter directions.

A star schema with fact and dimension tables is recommended for most reports; common issues include ambiguous paths, many-to-many confusion, and circular relationships.

Building a model typically involves loading data, cleaning in Power Query, creating relationships, validating cardinality, and optimizing the schema.