Show related item django-CodePudding

I have the following models:

class Category(models.Model): name = models.CharField(max_length=255)

class Element(models.Model):

category = models.ForeignKey(Category)
name = models.CharField(max_length=255)

class Topic(models.Model):

category = models.ForeignKey(Category)

element = models.ForeignKey(Element) name = models.CharField(max_length=255)

I basically need to add New topic in catégory id =1 and get only a list of élément belongs to category 1

I have created a view New topic in category id =1, but for fields element in form i get all elements for all categories

CodePudding user response：

To do this, you should add a related_name to the category field in the Element model.

category = models.ForeignKey(Category, related_name='elements')

Then when you have a topic object you can access the elements for the topic's category by doing obj.category.elements.

If you plan to get a list of posts in a category, you would do the same thing (obviously with a different name) to the FK from Topic to Category.

CodePudding user response：

Hellow,

Below models.py

class Category(models.Model):
    name = models.CharField(max_length=50, unique=True)
    description = models.CharField(max_length=150)

class Element(models.Model):
    category = models.ForeignKey(Category, related_name='elements', on_delete=models.CASCADE)
    element = models.CharField(max_length=50)

class Topic(models.Model):
    subject = models.CharField(max_length=255)
    element = models.ForeignKey(KPI, related_name='topics', on_delete=models.CASCADE)
    category = models.ForeignKey(Category, related_name='tickets', on_delete=models.CASCADE)
    created_by = models.ForeignKey(User, related_name='tickets', on_delete=models.CASCADE)
    created_date = models.DateTimeField(auto_now_add=True)

views.py

def new_topic(request, category_id):
    category = get_object_or_404(Category, pk=category_id)
    kpi = KPI.objects.select_related().filter(category=category_id)
    #user = User.objects.first()
    if request.method == "POST":
        form = NewTopicForm(request.POST)

        if form.is_valid():
           topic = form.save(commit=False)
           topic.category = category
           topic.created_by = request.user
           topic.save()

       

           post = Post.objects.create(
                message=form.cleaned_data.get('message'),
                
                topic=topic
           )
           return redirect('category_topic', category_id=category.pk)
    else:

        form = NewTopicForm()

    return render(request, 'new_topic.html', {'category': category, 'form':form}
                  )

forms.py

class NewTopicForm(forms.ModelForm):

    message = forms.CharField(widget=forms.Textarea, max_length=6000)

    class Meta:
        model = Topic
        fields = ['subject', 'issue_date', 'message', 'element']

Some elements was created by admin interface such as

Category_1 elements_1 Category_1 elemnts_2 Category_2 elements_3

The quesion is when I need to create new topic in category_1, I need to show only elements belongs to category 1 not all elements

Thank you