I would like to retrieve lesson present in chapter model.

class Course(models.Model):
    category = models.ForeignKey(Category, on_delete=models.CASCADE)
    title = models.CharField(max_length=200)
    description = models.TextField()
    price = models.FloatField()

class Chapter(models.Model):
    title = models.CharField( max_length=200)
    course = models.ForeignKey(Course, on_delete=models.CASCADE)
    is_active = models.BooleanField(default=True)

class Lesson(models.Model):
    chapter = models.ForeignKey(Chapter, on_delete=models.CASCADE)
    title = models.CharField(max_length=200)
    video_url = models.URLField()

Below is my views.py:

def courseDetail(request, category_slug, course_slug):
    try:
        course_detail = Course.objects.get(category__slug=category_slug, slug=course_slug)
        all_chapters = Chapter.objects.filter(course=course_detail).order_by('created_date')
        all_lessons = Lesson.objects.filter(chapter__id__in=all_chapters)
    except Exception as e:
        raise e

    context = {
        'course_detail': course_detail,
        'all_chapters': all_chapters,
        'all_lessons': all_lessons,
    }
    return render(request, 'course-detail.html', context)

Here is my urls.py:

urlpatterns = [
    path('<slug:category_slug>/<slug:course_slug>/', views.courseDetail, name='course-detail'),
]

I am trying to explain my issue with the bellow example Ex:

1. Course: "Course 1"
2. In that course i have 2 chapters i.e Chapter 1, Chapter 2
3. And each chapter contains 3 lessons. i.e Chapter 1 contains Lesson 1, Lesson 2, Lesson 3 and Chapter 2 contains Lesson 4, Lesson 5, Lesson 6.

So when I wanted to show respective lessons inside the respective chapters it's showing all the lessons in both the chapters. How to fix this?

CodePudding user response：

Not entirely sure what you want to do but my hunch is replace the following:

all_lesson_urls = LessonURL.objects.filter(category__id__in=all_lessons)

with

all_lesson_urls = LessonURL.objects.filter(category__id__in=all_lessons).values("category__title", "title")

CodePudding user response：

I am assuming that you are getting all_chapters from Chapter model successfully, so to fetch all_lessons from Lesson model, do this query:

all_chapters = Chapter.objects.filter(course=course_detail).order_by('created_date')
list_of_all_chapters=list(all_chapters)
all_lessons = Lesson.objects.filter(chapter__in=[i.id for i in list_of_all_chapters])

Since __in lookup is used to filter in range of values from list.