I was interested in creating a generic helper function to get the instrumented list associated with a "RelationshipProperty" for a Model, you can get the relationship from inspect(model).mapper.relationships.items(), but the relationship is just the RelationshipProperty object and *not* the InstrumentedList. I could not see a way to get the instrumented list from the relationship and was wondering if I was missing something or if we really must use getattr(model, property_name) to get the InstrumentedList.
I also noticed that I couldn't directly set the instrumented list values from the relationship; I can do add/remove/extend operations on the list but not e.g. `relationship = [item1, item2, item3,]`, for that I had to use setattr(model, relationship_name, values_array) Any feedback on my approach or if there is a better way to do this would be appreciated! def type_query(type, id): type_query = g.session.query(type).filter_by(id=id).one() return type_query def get_relationship_from_model(parent_entity, relationship_model): relationship_label = None for label, r in inspect(parent_entity).mapper.relationships.items(): if r.entity.class_ == relationship_model: relationship_label = label break relationship = getattr(parent_entity, relationship_label) return relationship_label, relationship def update_list(relationship_model, entity_model, operation: str, id_list: Optional[List[UUID]] = None): """ id list = ids to add or remove from relationship relationship_type = the `type` of the relationship on entity model, e.g... entity_model = the model whose relationships are being updated operation = add or remove :param id_list: :param relationship_model: :param entity_model: :param operation: :return: """ if not id_list: return entity_model # e.g. CvMeasurementAttribute -> cv_measurement_attributes relationship_label, relationship = get_relationship_from_model(parent_entity=entity_model, relationship_model=relationship_model) entities_to_relate = [ type_query(type=relationship_model, id=id_) for id_ in id_list ] if operation == "add": relationship.extend(entities_to_relate) elif operation == "remove": for entity in entities_to_relate: relationship.remove(entity) else: setattr(entity_model, relationship_label, entities_to_relate) return entity_model -- SQLAlchemy - The Python SQL Toolkit and Object Relational Mapper http://www.sqlalchemy.org/ To post example code, please provide an MCVE: Minimal, Complete, and Verifiable Example. See http://stackoverflow.com/help/mcve for a full description. --- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sqlalchemy/323bfe66-3d7d-4fe1-87cf-feb4ca9566bfo%40googlegroups.com.