Because I also want to be able to go the other way. I want to be able to get the a attribute from any given F.
On Tuesday, March 24, 2015 at 4:47:42 PM UTC-7, Michael Bayer wrote: > > > > Andrew Millspaugh <[email protected] <javascript:>> wrote: > > > Yes, I got the style from there. > > > > I have a great great great great grandchild that I need to be able to > access by the great great great great grandparent id. How would you > recommend doing that, then? I don't want to have to write f_instances = > F.query.join(F.e).join(E.d).join(D.c).join(C.b).join(B.a).filter(A.id == > 1).all() just to find the F's that have A.id 1. > > If that’s all you need, why not put an accessor on F? > > class F(Base): > # … > > @classmethod > def join_to_a(cls): > return (F.e, E.d, D.c, C.b, B.a) > > > then: > > F.query.join(*F.join_to_a()) > > > > > > > > > On Tuesday, March 24, 2015 at 6:28:31 AM UTC-7, Michael Bayer wrote: > > > > > > Andrew Millspaugh <[email protected]> wrote: > > > > > I've got a class hierarchy that looks something like this: > > > > > > [ A ] 1--------* [ B ] 1---------* [ C ] 1----------* [ D ] > 1--------0..1 [ E ] 1..*----------0..1 [ F ] > > > > > > org proj ticket snap > bidlimit ticketset > > > > > > And I'm trying to add a relationship from A to F with a backref. The > relationship definition (on the A model) looks like: > > > > > > f = DB.relationship('F', > > > secondary=( > > > 'join(F, E, F.id == E.f_id)' > > > '.join(D, E.d_id == D.id)' > > > '.join(C, D.c_id == C.id)' > > > '.join(B, C.b_id == B.id)' > > > ), > > > primaryjoin='A.id == B.a_id', > > > secondaryjoin='E.f_id == F.id', > > > backref=DB.backref('a', uselist=False), viewonly=True > > > ) > > > > > > Now, if I query A.f, I get all of the F's, instead of just the ones > which have a relationship with A. I'm sure I'm missing something simple, > but I can't seem to find it... Any help out there? > > > > what does your SQL output say? Is this query(A).join(A.f) or the “f” > > attribute on an existing “A”? I’m assuming you got this style from > > > http://docs.sqlalchemy.org/en/rel_0_9/orm/join_conditions.html#composite-secondary-joins, > > > > note that its experimental and not well supported. In most cases you > should > > deal with individual relationships between each class. > > > > > -- > > > 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 [email protected]. > > > To post to this group, send email to [email protected]. > > > Visit this group at http://groups.google.com/group/sqlalchemy. > > > For more options, visit https://groups.google.com/d/optout. > > > > -- > > 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 [email protected] <javascript:>. > > To post to this group, send email to [email protected] > <javascript:>. > > Visit this group at http://groups.google.com/group/sqlalchemy. > > For more options, visit https://groups.google.com/d/optout. > -- 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.
