saving multiple models in django

Question

i need some help in my django project. i am new and am trying to save data to three models in view form. I am new to django and am trying to develop a web app for a farm management. My form i want to register a farm. i have three models, which are related and i want them to be save to the database from on function.

The model has three models as Phonenumbers, address and farm.

Model.py

from django.db import models
from django.contrib.auth.models import User
from datetime import datetime, date
class Farms(models.Model):
    farm_name = models.CharField(max_length=200, blank = True)
    recorded_by = models.ForeignKey(User, default= None, null=True, on_delete=models.CASCADE)

    def __str__(self):
        return self.farm_name

COUNTRY_CHOICES = (
    ('Nig','Nigeria'),
    ('AF', 'Afghanistan'),
    ('AL' ,'Albania'),
    ('DZ' , 'Algeria'),
    ('AX' , 'Aland'),
    ('AS' , 'American'),
    ('AI' , 'Anguilla'),
    ( 'AD' , 'Andorra'),
    ('AO' , 'Angola'),
    ('AN' ,' Antilles - Netherlands'),
)
class Address(models.Model):

    street_name = models.CharField(max_length = 200, blank = True)
    street_no = models.CharField(max_length = 50, blank = True)
    city = models.CharField(max_length = 200)
    state = models.CharField(max_length = 200)
    country = models.CharField(max_length = 200, choices=COUNTRY_CHOICES, default='Nig')
    farms = models.ForeignKey(Farms, on_delete=models.CASCADE)

class Telephone(models.Model):
    phonenumber = models.CharField(max_length = 200)
    farms= models.ForeignKey(Farms, on_delete=models.CASCADE)

    def __str__(self):
        return self.phonenumber

Form.py

from django import forms
from . import models

class CreateFarmsForm(forms.ModelForm):
    class Meta:
        model = models.Farms
        fields = ['farm_name']

class TelephoneCreateForm(forms.ModelForm):
    class Meta:
        model = models.Telephone
        fields = ['phonenumber']
        labels = {
            'phonenumber': 'Phone Number'
        }

class AddressCreateForm(forms.ModelForm):
    class Meta:
        model = models.Address
        fields = ['street_name', 'street_no', 'city', 'state','country']
        labels = {
            'street_name': 'Street Name',
            'street_no': 'street No'
        }

class DateInput(forms.DateInput):
    input_type = "date"

    def __init__(self, **kwargs):
        kwargs["format"] = "%Y-%m-%d"
        super().__init__(**kwargs)

Farm.html

{% extends "livestock/livestock_base.html" %}
{% load crispy_forms_tags %}
{% block livestock%}
                      
                             
                                 
                          
                               {% csrf_token %}
                                  
                              
                              {{farm_form.farm_name | as_crispy_field}}
                                  
                              
                                   {{phone_form.phonenumber | as_crispy_field}}
                                  
                                      
                              
                              
                              {{address_form.street_name | as_crispy_field}}
                                  
                                  
                              {{address_form.street_no | as_crispy_field}}
                                  
                                  
                                
                              
                              {{address_form.city | as_crispy_field}}
                                  
                                    
                              {{address_form.state | as_crispy_field}}
                                  
                                  
                              
                              {{address_form.country | as_crispy_field}}
                                  
                              
                                
                                
                          
                                 
                             
                      
{% endblock livestock%}

Views.py

def farm_name(request):
    if request.method == 'POST':
        farm_form = forms.CreateFarmsForm(request.POST)
        phone_form = forms.TelephoneCreateForm(request.POST)
        address_form = forms.AddressCreateForm(request.POST)
        if farm_form.is_valid and phone_form.is_valid and address_form.is_valid:
            farm=farm_form.save(commit=False)
            farm.recorded_by = request.user
            farm.save()

            phone=phone_form.save(False)
            phone.farm = farm
            phone.save()
            address = address_form.save(False)
            address.farm = farm
            address.save()

    farm_form = forms.CreateFarmsForm()
    phone_form = forms.TelephoneCreateForm()
    address_form = forms.AddressCreateForm()
    context = {'farm_form':farm_form, 'phone_form':phone_form, 'address_form':address_form,}
    return render(request, "livestock/farm_name.html", context)

This is the error message am getting

IntegrityError at /farm_name/
null value in column "farms_id" violates not-null constraint
DETAIL:  Failing row contains (13, 07065531350, null).
Request Method: POST
Request URL:    http://127.0.0.1:8000/farm_name/
Django Version: 3.0.5
Exception Type: IntegrityError
Exception Value:    
null value in column "farms_id" violates not-null constraint
DETAIL:  Failing row contains (13, 07065531350, null).
Exception Location: /home/william/djangoprojects/my_env/lib/python3.6/site-packages/django/db/backends/utils.py in _execute, line 86
Python Executable:  /home/william/djangoprojects/my_env/bin/python
Python Version: 3.6.9
Python Path:    
['/home/william/djangoprojects/wabokeglobal',
 '/usr/lib/python36.zip',
 '/usr/lib/python3.6',
 '/usr/lib/python3.6/lib-dynload',
 '/home/william/djangoprojects/my_env/lib/python3.6/site-packages']
Server time:    Sat, 23 May 2020 12:08:04 +0000

I have been on it for the past two days. please i need some help to continue.

user_171927 · Answer

In your Address and Telephone models you are creating foreign keys with the name farms. But in your view you trying to assign farm.

If you change your models as following and migrate the problem will be solved.

class Address(models.Model):

    street_name = models.CharField(max_length = 200, blank = True)
    street_no = models.CharField(max_length = 50, blank = True)
    city = models.CharField(max_length = 200)
    state = models.CharField(max_length = 200)
    country = models.CharField(max_length = 200, choices=COUNTRY_CHOICES, default='Nig')
    farm = models.ForeignKey(Farms, on_delete=models.CASCADE)

class Telephone(models.Model):
    phonenumber = models.CharField(max_length = 200)
    farm = models.ForeignKey(Farms, on_delete=models.CASCADE)

    def __str__(self):
        return self.phonenumber

saving multiple models in django

1 Answers