On Aug 25, 2008, at 12:22 PM, Hermann Himmelbauer wrote:
> > Hi, > I'm wondering if the following is possible with mappers: > > I have two tables A and B, whereas B is referenced by A. What I need > is a > special mapper for A that returns all referenced rows in B except > those, that > have a specific value in one column of the row, e.g.: > > Table A: > id, sometext, reftoB > 1, xyz, 1 > 2, abc, 2 > > Table B: > id, sometext > 1, foo > 2, NOTTHISONE <- Should not be returned by the mapper > > Is there a simple way to achieve this? > I'm not 100% clear on what you're asking since it seems like you are looking for a list of "A" based on something in B, but you said "returns all referenced rows in B". If you just wanted all Bs without "sometext=NOTTHISONE" thats just query(B).filter(B.sometext! ='NOTTHISONE'). Assuming you want the "A"s, the usual way to do this is to use a NOT EXISTS clause, which the ORM provides most easily along a relation(). If A has a relation to B which joins on reftoB, you'd say: session.query(A).filter(~A.b.has(B.sometext=='NOTTHISONE')) --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
