项目对象没有属性"review_set“

Question

我收到一个错误，当我尝试使用Numpy获取评分的平均值时，显示为Project object has no attribute review_set。

HTML看起来像这样，有什么问题吗？

<h5>{{ project.review.count }} reviews ({{ 
project.average_design | floatformat }} average rating of design)</h5>
<h5>{{ project.review.count }} reviews ({{ 
project.average_content | floatformat }} average rating of content)</h5>
<h5>{{ project.review.count }} reviews ({{ project.average_usability | floatformat }} average rating of usability)</h5>

型号：

class Project(models.Model):
    title = models.TextField(max_length=200, null=True, blank=True, default="title")
    project_image = models.ImageField(upload_to='picture/', null=True, blank=True)
    description = models.TextField()
    project_url=models.URLField(max_length=250)
    def average_design(self):
        design_ratings = list(map(lambda x: x.design_rating, self.review_set.all()))
        return np.mean(design_ratings)

    def average_usability(self):
        usability_ratings = list(map(lambda x: x.usability_rating, self.review_set.all()))
        return np.mean(usability_ratings)

    def average_content(self):
        content_ratings = list(map(lambda x: x.content_rating, self.review_set.all()))
        return np.mean(content_ratings)



class Review(models.Model):
    RATING_CHOICES = (
        (1, '1'),
        (2, '2'),
        (3, '3'),
        (4, '4'),
        (5, '5'),
        (6, '6'),
        (7, '7'),
        (8, '8'),
        (9, '9'),
        (10, '10'),

    )
    project = models.ForeignKey(Project, null=True, blank=True, on_delete=models.CASCADE, related_name="review")
    user = models.ForeignKey(User, null=True, blank=True, on_delete=models.CASCADE, related_name='user')
    image = models.ForeignKey(Image, on_delete=models.CASCADE, related_name="project", null=True, blank=True)
    comment = models.TextField()
    design_rating = models.IntegerField(choices=RATING_CHOICES, null=True, blank=True)
    usability_rating = models.IntegerField(choices=RATING_CHOICES, null=True, blank=True)
    content_rating = models.IntegerField(choices=RATING_CHOICES, null=True, blank=True)

Answer 1

你有related_name="review"。

project = models.ForeignKey(Project, null=True, blank=True, on_delete=models.CASCADE, related_name="review")

因此，您应该使用self.review.all()而不是self.review_set.all()。

如果你使用related_name="reviews"会更清楚(因为每个项目可以有多个评论)。

project = models.ForeignKey(Project, null=True, blank=True, on_delete=models.CASCADE, related_name="reviews")

然后你可以使用self.reviews.all()。

请注意，将related_name="user"和related_name="project"用于其他外键是没有意义的。它们分别用于获取给定用户和图片的相关评论，因此最好对这两个用户都使用related_name="reviews"。

Answer 2

谢谢，它起作用了。我将related_name编辑为"reviews“，并在数据库上进行了迁移。