The thing is that "Content" is a kind of abstract, I never add "Content" directly but rather objects which inherits of "Content".
I'll take a look at your scripts, thanks ! Julien On Tue, 2008-12-09 at 16:06 +0200, [EMAIL PROTECTED] wrote: > more things, u have polymorhism, but u do not specify identity for > Content; and things that look like many to one are one to many > (type). > > attached is the model as i understood it, expressed in dbcook; and the > SA-setup generated by it (tables+mappers). see for yourself if u have > anything else missing. i guess most verbose primary_join/remote_side > etc are not needed but it does fill them always. > > > On Tuesday 09 December 2008 15:44:07 Julien Cigar wrote: > > On Tue, 2008-12-09 at 13:05 +0200, [EMAIL PROTECTED] wrote: > > > not sure if that is the problem, but are Folder.items and > > > FolterContent.folder the reciprocal ends of same relation? > > > then u need only one of those, with backref. > > > > Hi, > > > > "Folder" is a "Content". A "Folder" can contains one or more > > "Content" through the "folder_content" table which is represented > > by the "FolderContent" association object, so FolderContent has a > > reference to a "Content" and a "Folder" (which is a "Content"). > > It's this "FolderContent" list which is accessible through the > > "Folder.items" property. In "FolderContent" I'd like to have a > > property to the corresponding "Content" and the corresponding > > "Folder" (which is a "Content", I suspect that the problem is > > here). So in my "FolderContent" mapper I added 'content' : > > relation(Content), which works. However 'folder' : relation(Folder) > > doesn't (although foreign keys are there, and I presume that > > SQLAlchemy use them to detect join points ..), so I wonder why it > > works for one and not for the other .. :) > > > > It sounds a bit complicated on paper, but in fact it's very simple. > > > > Thanks, > > Julien > > > > > On Tuesday 09 December 2008 12:08:02 Julien Cigar wrote: > > > > Dear SQLAlchemy users, > > > > > > > > I'm playing with inheritance for a CMS-like application. It's > > > > very usefull as it greatly simplifies the code. > > > > > > > > Here is my SQL script http://pastebin.com/f7c5297c8 and here is > > > > my python code (mappers, etc) http://pastebin.com/f1e2738ba > > > > (Not everything is shown...) > > > > > > > > As you can see, everything inherits from a "Content". "Folder" > > > > are special "Content" which act as containers for one or more > > > > "Content" through the "FolderContent" object (folder_content > > > > table). > > > > > > > > The problem is at line 128 of the second paste, SQLAlchemy is > > > > unable to determine the join condition to the "Folder" > > > > ("folder" table) which seems strange because folder_content > > > > table has explicitely a foreign key to the "folder" table (line > > > > 70 of the first paste). > > > > > > > > When I try to get a specific FolderContent through : > > > > >>> model.FolderContent.query.get((12,6)) > > > > > > > > I get a: > > > > > > > > "ArgumentError: Could not determine join condition between > > > > parent/child tables on relation FolderContent.folder. Specify > > > > a 'primaryjoin' expression. If this is a many-to-many > > > > relation, 'secondaryjoin' is needed as well." > > > > > > > > My question is: do I need to explicitely specify the join > > > > condition when inheritance is involved ? Why is SQLAlchemy able > > > > to detect the join condition for my "Content" (line 127) but > > > > not for my "Folder" (line 128) ? > > > > > > > > In advance thanks for your answers > > > > > > > > Best regards, > > > > Julien > > > > > -- Julien Cigar Belgian Biodiversity Platform http://www.biodiversity.be Université Libre de Bruxelles (ULB) Campus de la Plaine CP 257 Bâtiment NO, Bureau 4 N4 115C (Niveau 4) Boulevard du Triomphe, entrée ULB 2 B-1050 Bruxelles Mail: [EMAIL PROTECTED] @biobel: http://biobel.biodiversity.be/person/show/471 Tel : 02 650 57 52 --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
