How to access foreign key in a django template? (DetailView)

问题

I want to display products in a Campaign DetailView template.

In my project each campaign has a shop which contains products, so the flow is like,

Campaign --> Shop --> Products

Campaign models.py

class Campaign(models.Model):
     team = models.OneToOneField(Team, related_name='campaigns', on_delete=models.CASCADE, null=True, blank=True)
     shop = models.OneToOneField(shop_models.Shop, on_delete=models.CASCADE, null=True, blank=True)

Shop models.py

class Product(models.Model):
     title =         models.CharField(max_length=100)
     description =   models.CharField(max_length=700, null=True, blank=True)
     price  =        models.DecimalField(max_digits=10, decimal_places=0)

class Shop(models.Model):
     product  =  models.OneToOneField(Product, related_name='shop_product', on_delete=models.CASCADE, null=True, blank=True)
     product2 =  models.OneToOneField(Product, related_name='shop_product2', on_delete=models.CASCADE, null=True, blank=True)
     product3 =  models.OneToOneField(Product, related_name='shop_product3', on_delete=models.CASCADE, null=True, blank=True)

DetailView

class CampaignDetail(DetailView):
    model = Campaign
    form_class = CampaignForm
    pk_url_kwarg = 'pk'
    context_object_name = 'object'
    template_name = 'campaign_detail.html'

Template

{% for item in obj.shop_set.all %}
        <div class="plan">
            <a href="">

                <h4>{{ item.title }}</h4>
                <h5>{{ item.price }}</h5>
                <img src="{{ item.image.url }}" alt="">

            </a>
        </div>

Fields turned out to be empty in the template. Any help would be appreciated.

回答1:

As they are related by OneToOneField, then you can access the values of shop from campaign details view like this:

{{ obj.shop }}

And if you want to access the products, then do it like this:

{{ obj.shop.product.title }}
{{ obj.shop.product.price }}

{{ obj.shop.product2.title }}
{{ obj.shop.product2.price }}

{{ obj.shop.product3.title }}
{{ obj.shop.product3.price }}

Update

Well, in that case I would recommend using ManyToMany relation between Product and Shop. So that, a product can be assigned to multiple shops, or a shop can be assigned to multiple product. Then you can define the relation like this:

class Shop(models.Model):
    products = models.ManyToManyField(Product)

and if you want iterate through products for a shop, you can do it like this:

{% for product in obj.shop.products.all %}
      {{ product.title }}
      {{ product.name }}
{% endfor %}

回答2:

Your models are wrong anyway, but especially if you want to use a for loop. You don't need the OneToOneFields from Shop to Product, you just want one ForeignKey from Product to Shop.

class Product(models.Model):
    shop = models.ForeignKey('Shop')

Now you can do:

{% for product in obj.shop.product_set.all %}
    {{ product.title }}
    {{ product.price }}
{% endfor %}

If you don't have any other fields on Shop at all, then you can delete that whole model and have the ForeignKey point directly at Campaign, then iterate over obj.product_set.all.

来源：https://stackoverflow.com/questions/54069689/how-to-access-foreign-key-in-a-django-template-detailview

标签

django

python-3.x

django-models

django-templates