Martin Stein wrote: > Hi everybody, > > In my db-setup, there is a one-to-many relationship with a backref that is > configured for eager loading (not the relation but the backref!). When I > access the child objects of the parent object, the query from sqlalchemy > joins back to the parent object (due to eager loading). In this case, the > join is unnecessary, since the parent object is already known. > > Is there something I am missing or a way to avoid the join?
Ok that's kind of interesting. as a general rule, the ORM doesn't like to make assumptions. such as here, there is a lazyloader on User.keywords, which says "query for these Keyword objects", without any knowledge of what that query is. the keywords.user attribute has an eager load on it so it just does what it's told. In this case, the idea would be User.keywords knows that its one-to-many and that the backref is many-to-one, and additionally that the many-to-one load is "simple", i.e. uses just a get(), and then sends a lazyload(Keyword.user) to the query. its an interesting idea which wouldn't be so hard to implement, although my nervousness would be about unforeseen side effects. feel free to file an enhancement ticket for it. in the short term, I would recommend just not using lazy=False, in favor of eagerload() for queries where you know you'll want to descend that deeply. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~----------~----~----~----~------~----~------~--~---
