Microsoft Power BI Data Analyst Practice Question

The correct answer is to remove duplicate rows and add an index column. In a star schema, the key column on the 'one' side of a one-to-many relationship must contain unique values. The best practice to resolve duplicate values in a dimension table is to remove the duplicate rows based on the business key (like 'ProductSKU') and then add an index column in Power Query. This new column acts as a surrogate key, providing a unique integer-based identifier for each row, which is optimal for model performance and relationship integrity.

Creating a composite key is a possible but less optimal solution, as joins on multiple columns or text columns are less performant than on a single integer key. Establishing a many-to-many relationship is not ideal as it is a workaround for the data quality issue, not a solution, and can lead to ambiguity and performance problems. Filtering rows from the 'Sales' fact table is incorrect as it would result in the loss of valid data and lead to inaccurate reports.