多對多查詢的正確方法（django）

Question

我正在嘗試獲取用戶收藏的書籍列表。 我可以從用戶那里拉出所有收藏夾的列表

myfavorites = Favorite.objects.filter(user=thisUser)" 

這將返回 user1 的 3 個收藏夾的正確列表，但是當我嘗試使用該列表來獲取書籍列表時

"myBooks" : Book.objects.filter(favorites=myfavorites), 

相反，我只得到一個對象（用戶添加到收藏夾的第一本書）。 查詢這個的正確方法是什么？

問題出在我的視圖還是模型中？

視圖.py

def books(request):
    if 'userid' not in request.session:
        return redirect('/')
    else:
        num = request.session['userid']
        thisUser = User.objects.get(id=num)
        myfavorites = Favorite.objects.filter(user=thisUser)
        context = {
            "user" : thisUser,
            "otherBooks" : Book.objects.exclude(favorites=myfavorites),
            "myBooks" : Book.objects.filter(favorites=myfavorites)          
        }
        return render (request, 'app1/books.html', context)

模型.py

class User(models.Model):
    first = models.CharField(max_length=30)
    last = models.CharField(max_length=30)
    email = models.CharField(max_length=40)
    password = models.CharField(max_length=40)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)
    objects = UserManager()

class Book(models.Model):
    title = models.CharField(max_length=45)
    author = models.CharField(max_length=30)
    desc = models.TextField()
    user = models.ForeignKey(User, related_name="books")
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)
    objects = BookManager()

class Favorite(models.Model):
    favorite = models.BooleanField()
    user = models.ForeignKey(User, related_name="favorites")
    book = models.ForeignKey(Book, related_name="favorites")
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

Answer 1

1 - 您可以進行反向查找：

my_books = Book.objects.filter(favorites__user=thisUser)

2 - 您可以先獲取最喜歡的圖書 ID，然后在Book過濾器中使用它們：

fav_book_ids = Favorite.objects.filter(user=thisUser).values_list("book_id", flat=True)
books = Book.objects.filter(id__in=list(fav_book_ids))