I thought it should work too, but I'm getting:
"InvalidRequestError: Could not find a FROM clause to join from. Tried
joining to <class 'app.models.Person2Topic'>, but got: Can't find any
foreign key relationships between 'message' and 'person_2_topic'."
If i have time this weekend I'll look into this. If i don't find a bug in
my code, I'll post a reproducable test-case on github.
On Friday, April 26, 2013 7:18:24 PM UTC-4, Michael Bayer wrote:
>
>
> On Apr 26, 2013, at 7:10 PM, Jonathan Vanasco
> <jona...@findmeon.com<javascript:>>
> wrote:
>
> > Given
> > class Person:
> > id
> >
> > class Topic:
> > id
> >
> > class Person2Topic :
> > id
> > topic_id - fkeys topic(id)
> > person_id - fkeys person(id)
> >
> > class Message:
> > id
> > person_id_author - fkeys person(id)
> > topic_id - fkeys topic(id)
> >
> >
> >
> > I wanted to select by joining the Person2Topic table directly, with a
> filter
> >
> > query( Message )\
> > join( Person2Topic ,(
> > Message.topic_id ==
> Person2Topic.topic_id ,
> > Person2Topic.person_id = 1
> > )
> >
> > This generates errors, because sqlalchemy doesn't have an fkey on
> Message.topic_id = Person2Topic.topic_id
> >
> > i can only figure out how to do query by doing intermediary joins
> >
> > query( Message )\
> > join( Topic , ( Message.topic_id == Topic.id ) )\
> > join( Person2Topic ,( Topic.id = Person2Topic.topic_id
> )\
> > filter( Person2Topic.person_id = 1 )
> >
> > is it possible to do a select like I originally wanted ?
>
> you can write out the join condition as you are (not sure what's the
> downside there), or if you're looking for a relationship() to do it you'd
> need to set up a primaryjoin + foreign_keys in the relationship() to join
> as you want. I'm not sure what other options would be here.
>
>
>
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