Forum Discussion
Understanding One to many relationship?
Great question, and it touches upon one of the fundamentals of how Vertipaq works.
Your choice of "item" from one or the other table has a profound impact on the displayed data. If you pick it from the "dimension" table (the 1 side of the relationship) then you perform an inner join with strict filtering. If you choose to use the field from the "fact" table (the M side) then that is more like a left outer join.
By the way, the first option is preferred. If you don't like the strictness you can check the box "show items with no data" in the columns/rows well.
Thanks! In my case, I need to keep all items rom the 1-side of the relationship as it contains the sales amounts. But I want to capture comments that were made on specific sales, this is why the M side does not contain all items. So a left outer join on the "M" side is not optimal for me, it should be on the 1-side.
However, believe it or not, I had never noticed the "show items with no data" button. So thanks a lot for explaining so clearly the behaviour of the filters as well as opening my eyes on this option I had overseen!!!!!!