Hello,
May be you want to subclass GenericForeignKey:
class GenericOneToOne(GenericForeignKey):
many_to_one = False
one_to_many = False
one_to_one = True
Though have not tried it so YMMV.
Kind regards
On Thu, May 31, 2018 at 8:59 PM, Vitor Barbosa wrote:
> Hello! This is my first question, so please excuse any mistakes.
>
> I'm using django 1.8 (working on migration to 2.0).
>
> I need to implement a one-to-one generic relation. To illustrate suppose I
> have three classes, the first representing and abstract class in a store
> and the other specific products which need extra information:
>
>
> AbstractProduct(models.Model):
>
> sale = GenericRelation('Sales')
> class Meta:
> abstract = True
>
> Books(AbstractProduct):
>
>
> Magazines(AbstractProduct):
>
>
>
> Now I need to create a models for 'Sales'. Each sale is of a specific
> product. Following https://docs.djangoproject.com/en/2.0/ref/contrib/
> contenttypes/#generic-relations I used:
>
> class Sales(models.Model):
>
> content_type = models.ForeignKey(...)
> object_id = models.PositiveIntegerField(...)
> content_object = GenericForeignKey('content_type', 'object_id')
>
>
> My problem is that by using this approach whenever I do
>
> >>> Books.objects.get(pk=1).sale
>
> I get back a manager since django does not know it is a one-to-one
> relation. And it makes me think that maybe I'm approaching this in the
> wrong way.
>
> My question is:
> (a) is this design a good solution for this problem? Is there a better
> approach? Has anyone solved a similar problem in a better way?
> (b) is there a way to create a generic One-To-One relation?
>
> I'm open to answers pointing to good blogs/books/articles which give a
> more formal approach to this kind of design issue, if you know a good one.
>
> Thanks in advance! Yours,
>
> Vitor.
>
>
> --
> Vitor Quintanilha Barbosa
>
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