Jean Jordaan wrote:

You could still delete the storage if you wanted to kill all stored relations, couldn't you?

Well, yes, which yet again makes me think this is not a good path forward. It feels to me that the relation either should be stored in the object, and indexed somewhere, or there should be one central secret invisible storage. The relationship between two objects should not be deletable from "outside" the object, that seems really weird. If the relationship really is stored outside the object, then the only way to delete that relationship should be through an API. (With reasonable exceptions, such as deleting the ZODB, and setting Application.__relations = None, or something like that).