Question

lately I found a weird behavior in Django. Then, I start thinking that what’s wrong is the way I’m doing the work.

Lets assume that we have 2 models

class A(models.Model):
    attr1 = models.CharField()
...

class B(models.Model):
    a = models.ForeignKey("A",
        related_name = "bs"
        blank = True,
        null = True)

So, if I have some items of B, without associations to A, say b1, b2, b3, when I set a new instance of A, say a1, if I query

a.bs.all()
b1, b2 and b3 are returned.

What’s wrong with it? When I create a new instance, it should not rise any relation. I know that b1,b2 and b3 have no relations, but they can’t be associated by default to any new instance.

Anyone know how to proceed in a Django way?

I know I can do the trick
if a1.id:
return []
else:
a1.bs.all()

But I think that’s not the right way to do this.

Can anyone help me?

Thank you in advance

Answer 1

This is a bug in Django and is currently marked as “design decision needed”:

https://code.djangoproject.com/ticket/14615