How can I get the Author model objects into a queryset through the foreign key of B model? I would like to use the Author objects in my template.

#Models.py
    
class Book(models.Model):
        name = models.CharField(max_length=5)

class Author(models.Model):
    # lots of fields

class B(models.Model):
    author = models.ForeignKey(Author)
    book = models.ForeignKey(Book)

selected_book = "ABC"
book = Book.objects.get(name=selected_book)
original_queryset = B.objects.filter(name=book)

for i in original_queryset:
    print(i.author) # returns what i want
    queryset = # get all i.author objects somehow

return render(request,"template.html", {"queryset": queryset}

CodePudding user response：

Remove the for loop. then add the following line after the original_queryset = B.objects.filter(name=book) line->

queryset = original_queryset.author

If this doesn't work then let me know. I hope I can help you.

You can rename your B model's author field to authors, that makes your code more meaningful because ForeignKey field can store many data. In your code, you have made your B model's author field as a ForeignKey field, which means books can have multiple authors. You can see the django documentation of ForeignKey reference. If you change as I told you then don't forget to run migration(python manage.py makemigrations and python manage.py migrate command in your cmd) and change the line queryset = original_queryset.author to queryset = original_queryset.authors

Another approach

You can pass the original_queryset in the context of the template,(i.e: {'queryset':original_queryset }) then in your template.html, you can add tages like this:

{% for book in queryset %}
<ul>
{% for author in book.author %}
<li>author.name</li>
....
{% endfor %}
</ul>
{% endfor %} 

By doing these, you can place your books and authors in your template nicely. If it still shows error, message me, I hope I can help you.