pl-300beginner
Fact vs Dimension
A simple way to tell the difference between fact tables and dimension tables in Power BI.
Mar 27, 2026•1 min read
pl-300beginner
Star Schema Explained
Learn what a star schema is, why it matters in Power BI, and how it appears in PL-300.
Mar 30, 2026• 1 min read
What it is
A star schema is a data modeling pattern where a central fact table connects to multiple dimension tables.
Why it matters
In Power BI, star schemas usually make models easier to understand, easier to maintain, and easier to query.
Example
A project cost model may have a FactProjectTransaction table connected to DimDate, DimProject, and DimEmployee.
Common mistakes
- putting everything into one very wide table
- connecting dimension tables directly to each other
- using many-to-many relationships when they are not needed
Exam angle
PL-300 questions often frame star schema as the preferred modeling pattern when the goal is clarity and performance.
Key takeaway
If you are not sure how to model a Power BI dataset, start by asking what the fact table is and what the dimensions are.