I am trying to model a sales situation where you can sell to a person or to a business with a contact person. I cannot figure out the proper way to do this. It seems like 2 tables would be incorrect. But how do I model a Customer table that can be a business or a person? Would I just have a boolean for "business" and an additional "business_name" field that would default to Null. But then I have to do an if/then on the columns and that seems like poor design. Any advice, direction, or links is appreciated.