Get django default model field value to be a parent attribute value

[Matlau Issu]

I want the default modB localField value to be the modA wantedField value corresponding to the foreign key. This would gives :

    class modA(models.Model):

        wantedField = models.CharField(max_length=9)

        [ ... other fields ...]

        def asDefault():

            return wantedField

    class modB(models.Model): 

        moda        = models.ForeignKey(modA)

        [ ... other fields ...]

        localField  = models.CharField(max_length=9,default=moda.asDefault)

        def save(self, *args, **kwargs):

            if self.pk is None:

                if self.moda and not self.localField:

                    self.localField = self.moda.wantedField

            super(modB, self).save(*args, **kwargs)

Also, would the approach be the same with any other field type ?

Anyway, for the moment it returns:

    AttributeError: 'ForeignKey' object has no attribute 'asDefault'

Thanks for your help

[Collin Anderson]

Hello,

The issue is with the "default=moda.asDefault". That won't work in this case. If you remove that, does your save method do what you are trying to do?

Collin