code: def delete_relationship(self, json_data, relationship_field, related_id_field, view_kwargs):
          
          self.before_delete_relationship(json_data, relationship_field, related_id_field, view_kwargs)
  
          obj = self.get_object(view_kwargs)
  
          if obj is None:
              url_field = getattr(self, 'url_field', 'id')
              filter_value = view_kwargs[url_field]
              raise ObjectNotFound('{}: {} not found'.format(self.model.__name__, filter_value),
                                   source={'parameter': url_field})
  
          if not hasattr(obj, relationship_field):
              raise RelationNotFound("{} has no attribute {}".format(obj.__class__.__name__, relationship_field))
  
          related_model = getattr(obj.__class__, relationship_field).property.mapper.class_
  
          updated = False
  
          if isinstance(json_data['data'], list):
              obj_ids = {str(getattr(obj__, related_id_field)) for obj__ in getattr(obj, relationship_field)}
  
              for obj_ in json_data['data']:
                  if obj_['id'] in obj_ids:
                      getattr(obj,
                              relationship_field).remove(self.get_related_object(related_model, related_id_field, obj_))
                      updated = True
          else:
              setattr(obj, relationship_field, None)
              updated = True
  
          try:
              self.session.commit()
          except JsonApiException as e:
              self.session.rollback()
              raise e
          except Exception as e:
              self.session.rollback()
              raise JsonApiException("Delete relationship error: " + str(e))
  
          self.after_delete_relationship(obj, updated, json_data, relationship_field, related_id_field, view_kwargs)
  
          return obj, updated
docs: Delete a relationship
  
          :param dict json_data: the request params
          :param str relationship_field: the model attribute used for relationship
          :param str related_id_field: the identifier field of the related model
          :param dict view_kwargs: kwargs from the resource view