Question

I created a project with Django and am trying to write from forms to db.
The model class has two classes :

class Contact(models.Model):
    name = models.CharField(max_length=200)
    birth_day = models.DateTimeField()
    address = models.CharField(max_length=200)

class PhoneNumber(models.Model):
    PHONETYPE_CHOICES = (
        (0, 'Home'),
        (1, 'Work'),
        (2, 'Fax'),
        (3, 'Mobile'),
        (4, 'Other'),
    )
    contact = models.ForeignKey(Contact)
    phone_type = models.CharField(max_length=255, choices=PHONETYPE_CHOICES)
    phonenumber = models.CharField(max_length=30) 

Now if I want to write to this with forms and I use only:

Name

Birthday

Address

Number type

Phone Number

as form fields.

I get:

IntegrityError x_phonenumber.contact_id may not be NULL

This is part of the view:

def main(request):
    if request.method == 'POST':
        form = UserForm(request.POST)
        if form.is_valid():
            name = form.cleaned_data['name'],
            birth_day = form.cleaned_data['birth_day'],
            address = form.cleaned_data['address'],
#            contact1= form.cleaned_data['id']
            phone_type = form.cleaned_data['phone_type']
            phonenumber = form.cleaned_data['phonenumber']
            contact = Contact(
                name = form.cleaned_data['name'],
                birth_day = form.cleaned_data['birth_day'],
                address = form.cleaned_data['address'],
            )
            contact.save()
            number = PhoneNumber(
#                contact1 = form.cleaned_data ['id']
                phone_type = form.cleaned_data['phone_type'],
                phonenumber = form.cleaned_data['phonenumber'],

            )
            number.save()

I know I have to fill in the ID of the person in that ForeignKey, but I thought that is what the ForeignKey will do for me.

The two commented out object “contact1” did not work. But that is basically what I want, add the id to this.

Also, Django always adds an _id primary key to every table (contact and Phonenumber).

So i did not get why, Django did not add to this.

How can I save this to db with the correct id, primary key etc..

Thanks

Answer 1

The ForeignKey can’t magically know which person it’s supposed to be pointing at, unless you tell it.

In your case, once you’ve done contact.save(), you now have a Contact instance, so you can use that.

number = PhoneNumber(
    contact = contact,
    phone_type = form.cleaned_data['phone_type'],
    phonenumber = form.cleaned_data['phonenumber'],
)
number.save()