On Wed, Dec 16, 2009 at 6:21 AM, Victor Hooi <victorh...@gmail.com> wrote: > heya, > > We have a small project where we need to store a series of exam > results for students. > > Some exams receive a grade out of 100, others are simply a pass/fail, > while others are given a one-word grade (e.g. pass, fail, credit, > distinction). > > In a sense, they all do map to a 0 to 100 scale (e.g. for the pass/ > fail, you can make it 0 and 100, while the pass/fail/credit/ > distinction can be mapped to other numbers. However apparently the > users don't want to store it that way, and want them each > differentiated. Also, I suppose you'd need to store somehow which type > of mark it was anyway, for when you need to represent it to the user. > > I was thinking of setting up abstract models to handle this, something > like: > > class AssessmentTask(models.Model): > name = models.CharField(max_length=20) > paper = models.FileField(upload_to='forms/examination') > date = models.DateField() > > class Meta: > abstract = True > > class GradedAssessmentTask(AssessmentTask): > mark = models.CharField(max_length=1, > choices=ASSESSMENT_GRADE_CHOICES) > > class PassFailAssessmentTask(AssessmentTask): > mark = models.BooleanField() > > class NumericalMarkAssessmentTask(AssessmentTask): > mark = models.PositiveIntegerField() > > class ExaminationRecord(models.Model): > assessment = models.OneToOneField(AssessmentTask) > > You could then create overridden methods to handle pass/fail checking > for each of those. The ExaminationRecord object contains a list of > assessments, each of which is of type AssessmentTask. > > However, Django complains with: > > AssertionError: OneToOneField cannot define a relation with > abstract class AssessmentTask > > So obviously that's not the right way to handle this. What is the > right way within Django to handle something like this? > > Cheers, > Victor >
store results as 0-100 integer and use second integer field to indicate what type of mark it is - then simply convert it - you can use method of your model -- You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-us...@googlegroups.com. To unsubscribe from this group, send email to django-users+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/django-users?hl=en.
