Here is my model

class MainCategory(models.Model):
    name = models.CharField(max_length=100)

    def __str__(self) :
        return self.name
    
class Category(models.Model):
    main_category = models.ForeignKey(MainCategory, on_delete=models.CASCADE, related_name="maincategory")
    name = models.CharField(max_length=100)

    def __str__(self) :
        return self.name + "--" + self.main_category.name
    
class SubCategory(models.Model):
    category = models.ForeignKey(Category, on_delete=models.CASCADE, related_name="category_name")
    name = models.CharField(max_length=100)

    def __str__(self) :
        return self.name

View

def Home(request):
    sliders = Slider.objects.all()
    banners = BannerArea.objects.all()
    main_category = MainCategory.objects.all()
    context = {
        'sliders' : sliders,
        'banners' : banners,
        'main_category' : main_category
    }
    return render(request, 'main/home.html', context)

I want to display Main Category and Sub category and category. Main Category is displayed but sub category and category are not displayed. Can you help me to fix this problem

Header.html files

<div class="cat__menu">
                                <nav id="mobile-menu" style="display: block;">
                                    <ul>

                                        {% for i in main_category %}

                                        <li>
                                            <a href="shop.html"> {{ i.name }} <i class="far fa-angle-down"></i></a>
                                            <ul class="mega-menu">

                                                {% for cat in i.category_set.all %}

                                                <li><a href="shop.html">{{cat.name}}</a>
                                                    <ul class="mega-item">
                                                        {% for sub_cat in cat.subcategory_set.all %}
                                                        <li><a href="product-details.html">{{sub_cat.name}}</a></li>
                                                        {% endfor %}
                                                        
                                                    </ul>
                                                </li>
                                                {% endfor %}
  
                                            </ul>
                                        </li>

                                        {% endfor %}
                                        
                                    </ul>
                                </nav>
                            </div>
  

I want to display Main Category and Sub category and category. Main Category is displayed but sub category and category are not displayed. Can you help me to fix this problem

>Solution :

It is not working because you have defined related name for reverse relationship. Hence instead of <modelname>_set you should use that related name, like this:

 {% for i in main_category %}
    {% for cat in i.maincategory.all %}
         {{ cat }}
        {% for sub_cat in cat.subcategory_set.all %}
         {{ sub }}
        {% endfor %}
    {% endfor %}
  {% endfor %}