Data warehouses have all sorts of different design approaches based on their different requirements, wouldn't this just be another one of them? I actually think

Data warehouses have all sorts of different design approaches based on their different requirements, wouldn't this just be another one of them? I actually think that having a way to alter the constraint to non-enforcing sounds like it'd be better for your situation anyway because you can then have your load performance but utilise the constraints with background / delayed process that checks the integrity because the information is still there in a standard form. Which sort of leads to .... I don't agree with your characterisation of foreign key constraints as business rules. They are genuine information about the structure of the data.