Re: inheritance, abstract base classes and generic foreign keys

[herr.klein...@googlemail.com]

On Apr 10, 12:10 pm, Malcolm Tredinnick <malc...@pointy-stick.com>
wrote:
> On Fri, 2009-04-10 at 02:34 -0700, herr.klein...@googlemail.com wrote:
> > Thanks Malcom.
>
> > All right lets see if i could put my real problem simpler. Lets say
> > you are the tutor of a programming course and you want to check the
> > programming assignments semi-automatically.
> > So you would set up a Task to which a student can submit a solution.
> > If the solution is accepted depends on various tests. For example does
> > the program compute the right output to a given input, is everything
> > well formated and right commented, is every occurrence of the students
> > name deleted from the code so that a reviewer that might know the
> > student can grade unbiased, etc.
> > These test are configureable for every assignment that uses them.
> > Every Test inherits a common interface(eg.  run_test()) from the
> > abstract test base class.
> > Now the first step is to assign a bunch of tests to an assignment.
> > This is problematic because different tests are different classes/
> > tables. A task could have one test trough a generic foreign link, but
> > again only one.
>
> You could probably do with one more level of indirection here.
> Assignments can contain a one-to-many to a model that contains a generic
> relation to the right type of test.
>
>         class Task(models.Model):
>            ...
>
>         class Attempt(models.Model):
>            task = models.ForeignKey(Task)
>            content_type = models.ForeignKey(ContentType)
>            object_id = models.IntegerField()
>            test = models.GenericForeignKey()
>
> The test / content_type / object_id collection point to your various
> test classes. You can then run through them with:
>
>         for attempt in task.attempt_set.all():
>            attempt.test.run_test(...)
>
> [...]
>
> > I hope that makes it a bit clearer.
>
> > Cage = Task
> > Animals = Tests
> > walk = run_test()
>
> > I think my analogy wasn't that bad.
>
> Whatever. When I said I couldn't understand it, I wasn't just making
> idle conversation. It wasn't at all clear what were classes or models in
> your original description. This time around, you talked about concrete
> models and assigning something to something else using many-to-many
> relations and so forth. It may well have made sense to you, but that's
> the least of concerns when asking for help.
>
> Regards,
> Malcolm


Thanks for your fast reply.

Thats a nice idea. Works great.
Now if i only could get the tests to appear inline in the task admin
page.
Do you think i could accomplish that by setting the formset in an
inlineModelAdmin to something else or do i think in the wrong
direction.

Greetings,
Daniel
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