this is standard relation() stuff thats documented in the ORM tutorial in "Querying with Joins".
On Aug 3, 2009, at 4:59 PM, thatsanicehatyouh...@mac.com wrote: > > Hi, > > I'm circling around an answer for a problem but am not quite getting > it. I have two tables: Plugging and Cartridge. Plugging has a to-one > relation to Cartridge, and the inverse relation is to-many. Cartridge > has a field called "number" and plugging has a field called "active". > I want to build a query to retrieve a single plugging, and this works > for me: > > plugging, cart = session.query(Plugging, > Cartridge).filter(Cartridge.number == > cartNo).filter(Plugging.cartridge_pk == > Cartridge.pk).filter(Plugging.active == True).one() > > This seems overly complicated - I shouldn't need to specify the > primary keys (pk) since the foreign keys are already defined (I'm > using autoload with postgresql). My first attempt at a query was this: > > plugging = session.query(Plugging).filter(Plugging.cartridge.number == > cartNo).one() > > ...but that turned out to be too optimistic (ignore for the moment > that I left out the "active" filter). What is the best practice for > simplifying the first query? > > Cheers, > Demitri > > > --~--~---------~--~----~------------~-------~--~----~ 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 sqlalchemy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~----------~----~----~----~------~----~------~--~---
