How to work around lack of support for foreign keys across databases in Django

Question

I know Django does not support foreign keys across multiple databases (originally Django 1.3 docs)

But I\'m looking for a workaround.

What doesn\'t work

Answer 1

Inspired by @Frans ' comment. My workaround is to do this in business layer. In the example given this question. I would set fruit to an IntegerField on Article, as "not to do integrity check in data layer".

class Fruit(models.Model):
    name = models.CharField()

class Article(models.Model):
    fruit = models.IntegerField()
    intro = models.TextField()

Then honor reference relation in application code (business layer). Take Django admin for example, in order to display fruit as a choice in Article's add page, you populate a list of choices for fruit manually.

# admin.py in App article
class ArticleAdmin(admin.ModelAdmin):
    class ArticleForm(forms.ModelForm):
        fields = ['fruit', 'intro']

        # populate choices for fruit
        choices = [(obj.id, obj.name) for obj in Fruit.objects.all()]
        widgets = {
            'fruit': forms.Select(choices=choices)}

    form = ArticleForm
    list_diaplay = ['fruit', 'intro']

Of course you may need to take care of form field validation (integrity check).