Question

I’m trying to model my app and I’ve come across this problem:

I have a Slides which can be images, text or videos.
Also, images and videos can be in many different slides and presentations of the same user.

I also want to store which presentation the slide belongs to and the insert date (slides must have an order).

class Slide(models.Model):
    user = models.ForeignKey(User)
    presentation = models.ForeignKey(Presentation)
    insert_date = models.DateTimeField(auto_now_add=True)

–

class Image(models.Model):
    def get_image_path(instance, filename):
        return os.path.join('users/images', str(instance.id), filename)

    user = models.ForeignKey(User)
    slide = models.ManyToManyField(Slide)
    image = models.ImageField(upload_to=get_image_path)
    insert_date = models.DateTimeField(, auto_now_add=True)

–

class SlideText(models.Model):
    slide = models.OneToOneField(Slide)
    text = models.TextField()

[Video model will be similar to Image]

Problems with this model are that a Slide can be empty, and that a slide can contain both Images and Texts (as well as Video) and it shouldn’t.

I can image that this would be a common problem: certain Item have some information related depeding on the “type of Item” (that’d be Slide of image, Slide of text…), so what’s the common solution ?

any help really appreciated! thanks!

Answer 1

Generic relations are what you want.