Django - Feeding only part of Foreignkey in models - django

Question

i'm new to django and as a exercise I want to make "home expenses".
I've already did simple model and form :
(from models)
#models.py
#these are the type (groceries/clothes/etc. )
class TypWydatku(models.Model):
typ_wydatku = models.CharField(max_length=25)
data_wpisu=models.DateField(auto_now_add=True)
#these are the actual input with dates/prices/etc
class Wpisy(models.Model):
data_zakupu=models.DateField(default=timezone.now())
data_wpisu=models.DateField(auto_now=True)
typ_wydatku=models.ForeignKey(TypWydatku)
kwota=models.FloatField('kwota')
uwagi=models.CharField(max_length=255, blank=True)
But now I would like to add another model, which will describe expenses connected to my car more specific. So I add another TypWydatku - Moto with id=3
Next step is to create new model with extra fields (mileage/ fuel tanked):
#models.py
(...)
class WpisyMoto(models.Model):
wpis=models.ForeignKey(Wpisy)
przebieg=models.IntegerField()
uwagi=models.CharField(max_length=200)
litry=models.FloatField()
#and more
I have the sipmlest forms as one can have rigth now :
# forms.py
class TypWydatkuForm(ModelForm):
class Meta:
model = TypWydatku
fields = '__all__'
class WpisyForm(ModelForm):
class Meta:
model = Wpisy
fields = '__all__'
class WpisyMotoForm(ModelForm):
class Meta:
model = WpisyMoto
fields = '__all__'
I would like to have choice field 'wpis' in the template, where i want to see onlythose which have 'typ_wydatku'=3. How should I do it ?

Answer 1

From the docs for the ModelChoiceField field (which is the form field type Django will use to represent the ForeignKey field), this can be achieved by setting the form field's queryset attribute:
class WpisyMotoForm(ModelForm):
class Meta:
model = WpisyMoto
fields = '__all__'
def __init__(self, *args, **kwargs):
super(WpisyMotoForm, self).__init__(*args, **kwargs)
self.fields["wpis"].queryset = Wpisy.objects.filter(typ_wydatku__pk=3)