类型对象“Book”没有属性“order_by”

Question

我有一个书模型：

class Book(models.Model):
    publish_house = models.ForeignKey(PublishHouse, on_delete=models.DO_NOTHING)
    author = models.ForeignKey(Author, on_delete=models.DO_NOTHING)
    title = models.CharField(max_length=50)
    price = models.DecimalField(max_digits=5, decimal_places=2)

    objects = models.Manager()

    img = models.ImageField(upload_to='books/', default='books/no.png')
    img_inside = models.ImageField(upload_to='books/', 
                              default='books/no_inside.png')
    is_available = models.BooleanField(default=True)
    book_date = models.DateTimeField(default=datetime.now, blank=True)
    is_best_selling = models.BooleanField()

    def __str__(self):
        return self.title

    class Meta:
        db_table = 'Book'

我想按日期在模板中显示书籍（显示最近添加的书籍），这是视图：

def index(request):
    new_books = Book.order_by('-book_date')[:4]
    bestselling_books = Book.objects.filter('is_best_selling')[:4]
    book_context = {
        'new_books': new_books,
        'bestselling_books': bestselling_books,
    }
    advertises = Advertise.objects.all()
    adv_context = {
        'advertises': advertises
    }
    return render(request, 'pages/index.html', adv_context, book_context)

我想按添加日期的顺序显示图书

它一直给出这个错误：

type object 'Book' has no attribute 'order_by'

Answer 1

你需要改变这一行

new_books = Book.objects.order_by('-book_date')[:4]

到

new_books = Book.objects.order_by('-book_date')[:4]

因为order_by 在模型管理器中可用。

更新：

def index(request):
    new_books = Book.order_by('-book_date')[:4]
    bestselling_books = Book.objects.filter(is_best_selling=True)[:4]
    advertises = Advertise.objects.all()
    book_context = {
        'new_books': new_books,
        'bestselling_books': bestselling_books,
        'advertises': advertises
    }

    return render(request, 'pages/index.html', book_context)

Answer 2

书没有属性order_by，它的经理有

所以你需要

Book.objects.order_by