So in Marketing Cloud I'm trying to get the field name from a data extension that is the relationship to the SubscriberKey;
E.g. let's say I know the DE customer key and I retrieve all fields via DataExtensionField soap API and in that list is one field that is the relationship to the SubscriberKey but it's unknown because it's each DE in our case is variable, where I'm having trouble is getting which field is the relation. In other words how would I get the SubscriberKey/ DE field relationship dynamically? I hope this makes sense.