Forum Discussion
Is Bidirectional filtering really that bad?
tmjones2 -
I see a couple of issues with your model below:
1. There are 2 different paths, and therefore 2 different ways, that Supplier could filter FactContract.
-Supplier filters FactContract directly. (intuitive)
-Supplier filters FactPrice, which then filters the Terminals to those which are listed for Suppliers in Fact Price. Finally, filter FactContract by this list of terminals. (unintuitive and wrong results, e.g. Contracts for other Suppliers would show up)
2. The Contract Price will be misleading if you filter on a Product, again because FactContract is not actually filtered by Product, but it is filtered by terminals associated with the product.
Cheers!
Nathan
Those are just models I grabbed off of Google images, just pretend like the fact table in the first image has multiple facts inside of it and the second image doesn't have any bidirectional filters (so that both models have two different facts). I don't see why the second model is any better, but I see multiple ways why it's worse.