title: Parent Child Relationships
body: <p>This regarding handling parent child relationships in PowerPivot. I am facing a situation where the "PATH" dax function is giving me trouble with the set of data provided to the function.</p>
  
  <p>My data set has a parent column and a column with the child ids. Roots of the hierarchies do not have a corresponding row in the child ids column. Due to this reason PowerPivot gives me the following error when the "PATH" function is applied:</p>
  
  <p>"Calculation error in column 'CS_Comp'[]: The value '10' in 'CS_Comp'[ParentCol] must also exist in 'CS_Comp'[ChildCol].  Please add the missing data and try again."</p>