On Dec 2, 2008, at 5:54 PM, Eric Ongerth wrote:
> Now when I want to find out whether a Foo has a relation to another > Foo, I have to check whether there exists any row in foo_relations > that has the given Foo as either as "this" OR "that". Also, what if I > need backrefs on the foo_relations mapper? The backref from 'this' > and the backref from 'that' would both point to something called a > foo, but they would have to be given separate labels in order ot not > be conflicting property names -- when really, I would not want to know > if a foo was the 'that' or the 'this' of some foo relation. > > So ideally in a case like this, I could set an option that says the > m:m relation is bidirectional, and that the backrefs for both foreign > keys in the m:m table should really point to the same place (or at > least be unioned together). > > I have a feeling that would violate some part of the RDBMS standards, > and I'm perfectly willing to go without or work around. This is more > of a philosophical point for learning's sake -- what do other people > do in such cases? you can.... store two rows in the association table, one for each direction. or provide an accessor which just unions together the forwards and backwards references between Foo objects. or make a readonly relation() that does the appropriate "OR" logic. I might even try combining both of those techniques somehow. --~--~---------~--~----~------------~-------~--~----~ 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 [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~----------~----~----~----~------~----~------~--~---
