⭐ Star Schema

What it is:
A simple data model where one central Fact Table is connected directly to multiple Dimension Tables.

Think of it as:
A wheel where the fact table is the hub and dimension tables are the spokes.

Key Points:

• Simple and easy to understand
• Faster queries and reporting
• Commonly used in Power BI and data warehouses
• Some data is repeated (redundant)

Healthcare Example:

Fact Table: Claims

• Claim Amount
• Paid Amount
• Number of Visits

Dimension Tables:

• Patient
• Provider
• Date
• Diagnosis

Question it can answer:
“How much did we pay for diabetes-related claims by provider and month?”

❄️ Snowflake Schema

What it is:
A more structured data model where dimension tables are broken into smaller related tables.

Think of it as:
A family tree with multiple branches instead of a simple star.

Key Points:

• More organized and less duplicate data
• Uses more table relationships (joins)
• Slightly slower queries
• Better for large and complex datasets

Healthcare Example:

Fact Table: Claims

Dimension Tables:

• Patient
• Provider
• Date

Provider Dimension Split Into:

• Provider
• Specialty
• Organization
• Network

Question it can answer:
“What was the total cost for cardiology providers within a specific health system and region?”

Easy Way to Remember

⭐ Star Schema = Speed & Simplicity
❄️ Snowflake Schema = Organization & Scalability

Healthcare Rule of Thumb:
Use Star Schema for reporting and dashboards.
Use Snowflake Schema when healthcare data becomes complex and highly interconnected.