Hi All, I am wondering if it is possible to describe in sqlalchemy the following relationship with the new features introduced since 0.9.2. I've been reading this document and it looks close to what I'm trying to achieve:
> http://docs.sqlalchemy.org/en/rel_0_9/orm/relationships.html#composite-secondary-joins As does this previous mailing list post: > https://groups.google.com/d/topic/sqlalchemy/ov-mYWA7XAM/discussion There is a pre-existing structure to deal with. I would rather not change the structure if it can be avoided, but may have to resort to doing so. Here are the tables: TableName (column, ...) > PersonAction (PersonID, ActionID) > PersonUnit (PersonID, UnitID) > DepartmentUnit (UnitID, DepartmentID) > ActionMeaning (DepartmentID, ActionID) It would be nice to be able to go from an ActionMeaning to a PersonAction and back again. To do that, a conversion between DepartmentName and DepartmentID needs to happen. Here are a few of the relationships: One PersonAction: one ActionMeaning One ActionMeaning: many PersonAction One PersonUnit many PersonAction One PersonUnit one DepartmentUnit One DepartmentID: many UnitID (therefore one ActionMeaning: many DepartmentUnit) One ActionMeaning: Many PersonUnit (via DepartmentUnit) I'm using the ORM and I would like to be able to write a property on the PersonAction which allows me to efficiently get to the ActionMeaning (preferably joinedload'ed), and likewise I would like to be able to go from an ActionMeaning to all of the related PersonActions. Is this possible? Or are there alternative tasteful strategies for dealing with this tricky structure? Life would be much easier if I had the DepartmentID on the PersonUnit... Keywords to help anyone searching in the future: Composite relationship between multiple tables Joining multiple tables in a relationship relationship secondary join primaryjoin secondaryjoin Thanks, - Peter -- 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.
