选择django中的后向关联

Question

我在写一个Django项目.

在 courses/models.py

class Category(models.Model):
    title = models.CharField(max_length=50)

class Language(models.Model):
    category = models.ForeignKey(Category, on_delete=models.CASCADE)
    title = models.CharField(max_length=50)

class Course(models.Model):
    name = models.CharField(max_length=250)
    language = models.ForeignKey(Language, on_delete=models.CASCADE)

我想得到所有列表,Category然后遍历每个Language指定的类别.

class Courses(ListView):
    template_name = 'courses/index.html'
    model = Course
    context_object_name = 'courses'

    def get_context_data(self, **kwargs):
        context = super(Courses, self).get_context_data(**kwargs)
        categories = Category.objects.all()
        context['categories'] = categories
        return context

在模板中courses/index.html我想显示基于类别的语言列表

{% for category in categories %}
    {{ category.title }}
    <li>lis of languages in this category</li>
{% endfor %}

如何循环反向关联数据？

Answer 1

Django创建了一个可以通过modelname_set密钥在模板中访问的关系.

在你的情况下,你必须迭代: category.language_set.all

{% for category in categories %}
    {{ category.title }}
    {% for language in category.language_set.all %}
        <li>{{ language.title }}</li>
    {% endfor %}
{% endfor %}