So basically, I want to make this relational database into a star schema. This would revolve around a sales fact table. Although I am confused as how to do so because there are two ways in which a sale is made. Either through a store sale or internet sale. That part is kind of messing with how I would build my facts and dimensions table. Do I just make the sales fact table include the store id and leave it as null if it were a internet sale, or do I make those two items a dimension such as internet sale dim and store sale dim?