Question

Consider these pseudo models:

class City(models.Model):
    name = models.CharField()
    region = models.ForeignKey(Region)

class Region(models.Model):
    name = models.CharField()
    country = models.ForeignKey(Country)

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

and a form like this:

class MyForm(forms.Form):
    city = forms.CharField()
    region = forms.CharField()
    country = models.CharField()

I would like my UpdateView to show the current values, so I have setup an initial like so:

model_initial = City.objects.filter(id=self.object.id).values()[0]

form = MyForm(initial=model_initial)

which is kinda stupid because self.object is already available so I could do the value mapping manually already

Anyway, this works but relationships aren’t captured, so I could do:

model_initial = City.objects.filter(id=self.object.id).values()[0]
model_initial.update({'region':Somequery, 'country':Somequery})

form = MyForm(initial=model_initial)

But that would pretty nasty and likely unneeded. I have tried to see what select_related hands me but calling values() on that query doenst return the extra fields.

so, Question: Whats a nice way to construct the initial dict in this case?

Answer 1

In Python, “nice” usually means “simple and readable”, so I’d personnaly gor for something like:

city =  self.object
initial = dict(
  name=city.name, 
  region=city.region.name, 
  country=city.region.country.name
  )

but a ModelForm might be a good solution too…