Django onetoonefield not saving instance

django, django-models, python

Solution

At first create `B` instance, assign attributes to it, call save on it (now it have id) and then assign it to `mashup.b`:

if cr:
     b = B()
else:
    if mashup.b is None:
        b = B()

#.... (assign values to b attributes)

b.save()
mashup.b = b
mashup.save()

Problem

I am working on an application where i have two models for the purpose of this question let's call them A and B. I want to have another model where I 'link' both A and B just to make it easy for me to find the instance of B that relates to A. So I came up with: ``` class ABLink(models.Model): a = models.OneToOneField(A, null=True) b = models.OneToOneField(B, null=True) ``` I use Django's post_save signal for model A to do the link: ``` mashup, cr = ABLink.objects.get_or_create(a=instance) if cr: mashup.b = B() else: if mashup.b is None: mashup.b = B() .... (assign values to mashup.b attributes) mashup.b.save() mashup.save() ``` The problem is mashup.b is never saved in the DB. On checking in phpMyAdmin b is set to NULL. Any idea what I may be doing wrong

Original source