1. Evaluation Context in DAX
Artur Konstantynov

2. Who am I
(Power) BI Developer
Lead of Kyiv Power BI User Group

3. Me and Power BI It was the first time I heard about Power BI
I’d been working as Power BI developer
and wanted to know more
I knew what I need to know
I'm sharing my knowledge

4. Agenda
What is Context
Row Context
Filter Context
Context switching

5. Clarification
Direction Knowing the direction of each relationship is critical to understand Evaluation Context Type The Vertipaq (xVelocity) engine is optimized to work with ONE to type of relationship.

6. What is Context
Albert Einstein. General theory of relativity or GTR.

7. Total Qty = SUM('Sales fact'[Quantity])
What is Context
Total Qty = SUM('Sales fact'[Quantity])

8. Row Context Exists in calculated columns
Exists in iterators and filter functions (SUMX, Filter etc.)
Does not support relationships

9. Filter Context Exists in visualizations
Automatically works with direction of filtering in relationships
Appears in CALCULATE() function
Measures contain a Filter Context

10. Evaluation Context switching
CALCULATE() function
It’s the only one function that can modify Context
Can switch Row to Filter Context
Every Measure contains Calculate
Filter Context Functions
(FILTER(), ALL() etc.)
Direction of filtering and CROSSFILTER()

11. Demo

12. References
Alberto Ferrari. Bidirectional relationships and ambiguity in DAX
Artur Konstantynov
DB Best
Kyiv Power BI User Group