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 --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to [email protected] 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 -~----------~----~----~----~------~----~------~--~---
x.generated.sa.py
Description: application/python
x.py
Description: application/python
