Your Power BI Report is Only as Good as Its Data Model
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Your Power BI Report is Only as Good as Its Data Model

Foundation for all Power BI reports and dashboards Directly impacts performance and speed

Your Power BI Report is Only as Good as Its Data Model, slide 1 of 101 / 10

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01Why Data Modeling Matters

  • Foundation for all Power BI reports and dashboards
  • Directly impacts performance and speed
  • Ensures accurate calculations and metrics
  • Simplifies the user experience for report consumers
  • Makes maintenance and changes easier later
  • Turns raw data into a trusted analytics asset
  • Separates amateurs from professionals

02Meet the Star Schema

  • The gold standard for Power BI data models
  • Central fact table surrounded by dimension tables
  • Fact tables hold measurable data (e.g., sales amount, quantity)
  • Dimension tables hold descriptive data (e.g., product, date, customer)
  • Designed for high performance and simplicity
  • Resembles a star in the relationship view
  • The recommended model by Microsoft

03The Snowflake Schema

  • A variation of the star schema
  • Dimension tables are normalized into multiple related tables
  • Can resemble a snowflake in the relationship view
  • May be necessary for complex, hierarchical dimensions
  • Generally not recommended for Power BI
  • Can lead to more complex models and DAX
  • May negatively impact query performance

04Star vs Snowflake: Choose Wisely

  • Prefer Star Schema for most Power BI scenarios
  • Star is simpler for end-users to understand
  • Star typically delivers better performance
  • Snowflake might be used for very large dimensions
  • Avoid snowflaking unless you have a specific reason
  • Always denormalize dimensions into single tables when possible
  • Your goal is simplicity and speed

05Relationship Best Practices

  • Use single-direction, filter cross-filtering
  • Avoid bidirectional relationships where possible
  • Always define the correct cardinality (one-to-many, etc.)
  • Hide unnecessary fields from report view
  • Ensure active relationships are set correctly
  • Use descriptive table and column names
  • Validate relationships with data preview

06Common Modeling Mistakes

  • Importing every available column from a source
  • Creating a single large, flat table
  • Using unnecessary bidirectional relationships
  • Leaving auto-date/time tables enabled
  • Not setting a date table for time intelligence
  • Building a model without business user input
  • Ignoring data types and format settings

07Pro Tips for Success

  • Start with a clear business question
  • Collaborate with business stakeholders on the design
  • Use a consistent and clear naming convention
  • Implement role-playing dimensions correctly
  • Leverage the Model View to organize tables
  • Document your model for future users
  • Test with real-world questions and data volumes

08Your Action Plan

  • Audit your existing models for star schema compliance
  • Review and simplify complex relationships
  • Eliminate any unnecessary columns from your tables
  • Set a designated date table for your time intelligence
  • Practice building a new model from scratch
  • Share your knowledge with your team
  • Build a solid foundation for better reports