Star Schemas

Separate facts from dimensions and arrange them in a star schema.

In this lesson you will

Identify facts and dimensions
Design a star schema for the solution

Key concepts

fact tabledimension tablegrainstar schema

The lesson

Fact tables record events with numbers — each sale, each budget line. Dimension tables describe how you slice them — products, branches, dates.

A star schema puts the fact table in the middle with dimensions around it, each linked by a one-to-many relationship. It is the recommended design for Power BI models.

Decide the grain of each fact table — one row per sale, or per day per branch — and keep it consistent.

Step by step

List facts and dimensions in the solution.
State the grain of each fact table.
Draw the star schema.
Check it against the report questions.

Practice activity

Design the star schema for the reporting solution.

Expected result: A documented schema that can answer every report question.

Check your understanding

What does a dimension table describe?

Show answer
The ways facts are sliced, such as products, branches or dates.
What is the grain of a fact table?

Show answer
What one row represents, such as one sale.

Taught live by an instructor — online or in person. Free course lessons are for self-study and do not lead to a certificate — see registration options.