Reservation -> packages is just a many-to-many relationship with the caveat that a reservation can have the same package more than once. Sqlalchemy will automatically dedube the packages collections which is not what I want. In order to avoid this I had to use reservation_packages as an association table instead. The proxy is needed to hide this detail. So those relationships work fine.
Everything is done through reservation.packages so I don't need all those extra backrefs. ReservationPackage.__init__ must accept a package object so that appending to the packages collection works. On Thu, Sep 24, 2015 at 3:32 PM, Jonathan Vanasco <jonat...@findmeon.com> wrote: > Your use of association_proxy seems odd to me. That plugin is normally > used to "cut out" the middleman when using a join with an association > pattern and avoid a hop/remount a relationship from one object onto another. > > With my understanding and use of that plugin, you're basically setting the > following shortcut, and most other behaviors are a side-effect. > > Reservation.packages == Reservation._packages_rel.package > > Since ReservationPackage has a primary key on `id`, it should be able to > handle non-unique combinations. > > These 2 both jumps out to me as potential problems : > > ReservationPackage- > package - there is no backref or back-populates. > package - should this have a uselist=False setting? > __init__ - this handles the package, but not the reservation ? > > Reservation- > package_rel - no backref or back-populates > > In my experience, the bulk of problems with 'collections' have happened > because of incomplete or improper relationships. I'd try setting up > everything with fully declared relationships (ie, back_populates) and see > how that affects the design of your relations and how the code runs. > > You can pretty much expect the collections to not work properly unless you > have backref/back-populates declared. That's the biggest issue and warning > sign to me -- sqlalchemy only knows half of your relationship info. > > -- > You received this message because you are subscribed to a topic in the > Google Groups "sqlalchemy" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/sqlalchemy/1Hf6wTv0PfU/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > sqlalchemy+unsubscr...@googlegroups.com. > To post to this group, send email to sqlalchemy@googlegroups.com. > 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 sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at http://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.
