When you import multiple datasets into Power BI, they act as separate islands of data. But just like islands in an archipelago, you can build bridges between them.
Building relationships allows you to combine data from various sources into a single view for integrated analysis.
Imagine you have separate datasets for sales, inventory, and customer info. By establishing relationships between them, you can start answering questions like:
- Which products are selling well in which regions?
- Which customers purchase the most of a certain product?
- What products need to be reordered based on sales trends?
Without relationships, each dataset gives you one piece of the puzzle. Connect them, and you get the full picture.
Relationships make it possible to create interactive reports and dashboards for richer insights. They also enable powerful DAX formulas by establishing common points between tables.
Building relationships in Power BI is straightforward:
- Identify the Key Columns
The first step is finding natural connecting points between your datasets – columns containing the same data types of values. For example, a customer ID column in the sales data and customer profile. These are known as key columns.
- Open the Edit Relationships View
In the toolbar, click the Manage Relationships icon (a Venn diagram). This opens the diagram view.
- Draw the Relationship Lines
Click and drag between the key columns you want to relate. Power BI will display the relationship line and automatically determine the cardinality (one-to-many, many-to-many, etc.)
- Set the Advanced Options
Open the advanced settings to define the cross-filtering behavior, cardinality, and more.
- Apply Changes
Make sure to click Apply Changes to save the relationships.
And that’s it – your datasets are now related together through the chosen key columns. Changes made to one side will be reflected where that data exists on the other side.
Pro tip: Want to explore how your tables are connected visually? Turn on the Table Mode view for a relationship map.
Here are some best practices to follow as you build and manage relationships:
- Choose your key columns wisely – Pick columns with unique, consistent values like IDs to avoid duplication.
- Watch the cardinality – Be mindful of one-to-many vs. many-to-many relationships.
- Review periodically – Relationships may need updating to stay relevant as data changes.
- Document your model – Add relationship descriptions in Power BI for clarity.
- Limit unnecessary cross-filtering – Restrict filters to optimize performance.
Following Power BI best practices around relationships will lead to accurate, high-performance models. The connected data gives you the flexibility to analyze information in new ways.