Django NOT NULL约束失败：shop_product.user_id

Question

I am new to Django and I am trying to learn by practicing with some project but I am stuck with this problem,

NOT NULL constraint failed: shop_product.user_id

models.py

from django.db import models
from django.conf import settings
from django.core.urlresolvers import reverse
class Category(models.Model):
    user = models.ForeignKey(settings.AUTH_USER_MODEL,
                             related_name='category_created')
    name = models.CharField(max_length=200, db_index=True)
    slug = models.SlugField(max_length=200, db_index=True, unique=True)

    class Meta:
        ordering = ('name',)
        verbose_name = 'category'
        verbose_name_plural = 'categories'

    def __str__(self):
        return self.name

class Product(models.Model):
    user = models.ForeignKey(settings.AUTH_USER_MODEL,
                             related_name='product_created')
    category = models.ForeignKey(Category, related_name='products')
    name = models.CharField(max_length=200, db_index=True)
    slug = models.SlugField(max_length=200, db_index=True)
    image = models.ImageField(upload_to='products/%Y/%m/%d', blank=True)
    description = models.TextField(blank=True)
    price = models.DecimalField(max_digits=10, decimal_places=2)
    stock = models.PositiveIntegerField()
    available = models.BooleanField(default=True)
    negiotiable = models.BooleanField(default=True)
    created = models.DateTimeField(auto_now_add=True)
    updated = models.DateTimeField(auto_now=True)
    users_like = models.ManyToManyField(settings.AUTH_USER_MODEL,
                                        related_name='product_liked',
                                        blank=True)

    class Meta:
        ordering = ('name',)
        index_together = (('id', 'slug'),)

    def __str__(self):
        return self.name
    def get_absolute_url(self):
        return reverse('products_detail',
                       args=[self.slug])

Here is my views.py but am not sure if there is problem with my views and I think the problem will have to be with my models....

views.py

from django.views.generic import *
from django.core.urlresolvers import reverse_lazy
from .models import Category, Product

class CategoryList(ListView):
    model = Category

class CategoryDetail(DetailView):
    model = Category

class ProductList(ListView):
    model = Product

class ProductDetail(DetailView):
    model = Product

class ProductCreate(CreateView):
    model = Product
    fields = ("category", 'name', 'image', 'description', 'price', 'stock','available', 'negiotiable')

class ProductUpdate(UpdateView):
    model = Product
    fields = ('name', 'image', 'description', 'price', 'stock','available', 'negiotiable')

class ProductDelete(DeleteView):
    model = Product
    success_url = reverse_lazy('product_list')

Please let me know what could be done.

Answer 1

Either Add User into list:

class ProductCreate(CreateView):
    model = Product
    fields = ["category", 'name', 'image', 'description', 'price','stock','available', 'negiotiable', 'user']

OR make sure Field must be null=true and blank=True.

class Product(models.Model):
    user = models.ForeignKey(settings.AUTH_USER_MODEL,
                         related_name='product_created', null=True, blank=True)

Answer 2

Add a form for your product,

class ProductForm(forms.ModelForm):

    class Meta:
        model = Product
        fields = "__all__"

Also, your user field must be null=True and blank=True .

Then in your create view,

class ProductCreate(CreateView):
    model = Product
    form_class = ProductForm

    def form_valid(self, form):
        form.instance.user = self.request.user
        form.save()
        return super(ProductCreate, self).form_valid(form)

Now, whenever a product is created, the user who created would be added as the user of the product.