Thank you very much for your precise answer. I think I misunderstood a
lot and I will go through the tutorial again.
On 28 Okt., 15:04, bruno desthuilliers <[EMAIL PROTECTED]>
wrote:
> On 28 oct, 14:05,DanielStrasser<[EMAIL PROTECTED]> wrote:
>
> > > You have a circular reference between students.models and
> > > lessons.models. The first want to import the second, which want to
> > > import the first, etc... This just can't work.
>
> > Thank you very much. I played around but I don't come to a solution. I
> > think I'll try again. I just don't understand where this circular
> > reference should be (Problem exists also if I remove them from one
> > place or another)
>
> Sorry, it appears I jumped to conclusion a bit too fast. Re-reading
> the traceback:
>
> 1/ students.models imports lessons.models.Lesson
> 2/ lessons.models.Lesson try to reference students.models.Student -
> which is not defined.
>
> IOW : you don't _actually_ have a circular reference, but you would
> have one if you tried to solve this NameError by import
> students.models in lessons.models.
>
> The solution is to declare the foreign key on Students using a
> app_label.model_name string instead of a model object, ie (not
> tested...) :
>
> class Lesson(models.Model):
> # ...
> student = models.ForeignKey('students.Student')
>
> cfhttp://docs.djangoproject.com/en/dev/ref/models/fields/#django.db.mod...
> for more on this.
>
> A bit OT, but using a models.ForeignKey here means that a Lesson can
> have *at most one* single student. I can't of course tell whether
> that's ok for your app, but it sure looks a bit weird to me.
>
> And while we're at it: given the existence of this foreign key, the
> Student.lesson_hours method mentioned in your first post should make
> use of it, ie:
>
> class Student(models.Model):
> # ...
> def lesson_hours(self):
> return self.lesson_set.count()
>
> HTH
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Django users" group.
To post to this group, send email to django-users@googlegroups.com
To unsubscribe from this group, send email to [EMAIL PROTECTED]
For more options, visit this group at
http://groups.google.com/group/django-users?hl=en
-~----------~----~----~----~------~----~------~--~---
