Analytics Software

I've been told different things by different people regarding how all of the cubes, relational db and Planning fit together so I'm wondering if anyone truly understands it. I'm trying to figure out how they all work together. We have a workforce cube, a financial cube and planning web app. Somehow they all work together with a relational db. When we load a dim using ODI it is reflected in the cubes but I am not sure how this works. Does the data from ODI go to the relational db which is somehow attached to the workforce cube and then through a refresh populate the financial cube? I really need to understand how this all works together.