Django extras() -逻辑/算法

Question

我有一个看起来是这样的

class Post(models.Model):
    user = models.ForeignKey(Profile, related_name='posts')

    created = models.DateTimeField(auto_now_add=True)
    description = models.CharField(max_length=100, null = True)

它有两个与之相关的模型：

class Comments(models.Model):
    user = models.ForeignKey(Profile, related_name='author')
    post = models.ForeignKey(Post, related_name='posts')


class Likes(models.Model):
    user = models.ForeignKey(Profile, related_name='liker')
    post = models.ForeignKey(Post, related_name='post' )
    created = models.DateTimeField(auto_now_add=True)

    class Meta:
        ordering = ('created',)

现在，逻辑基本上是计算出喜欢的数量+随时间衰减的评论数量：

likes + comments / now() - post.created

我已经创建了这个逻辑的sql版本，现在我使用django额外创建了：

s = Post.objects.extras(select={'post':'logic here...... WHERE id = %d} % **MISSING PIECE THAT ALLOWS ME TO ITERATE OVER THE POST OBJECTS**)

有人能帮我弄清楚丢失的那件东西是什么吗？我尝试使用Post.objects.all().id，但它无法工作，因为它是一个查询集。

如需更多信息，请提供任何帮助。

Answer 1

请允许我将相关名称更改为更有意义的名称。

class Post(models.Model):
    user = models.ForeignKey(Profile, related_name='posts')

class Comments(models.Model):
    user = models.ForeignKey(Profile, related_name='comments')
    post = models.ForeignKey(Post, related_name='comments')

class Likes(models.Model):
    user = models.ForeignKey(Profile, related_name='likes')
    post = models.ForeignKey(Post, related_name='likes' )

现在你可以做了

post = Post.objects.get(pk=1)
output = ( post.likes.all().count() + post.comments.all().count() ) / ( now() - post.created )

更新

class Post(models.Model):
    created_at = models.DateTimeField(auto_now_add=True)

    def output(self):
        return ( self.likes.all().count() + self.comments.all().count() ) / (datetime.datetime.now() - self.created_at).total_seconds()

thelist = sorted(Post.objects.all(), key: lambda p : p.output)

据我所知，您无法在与数据库无关的事情上对列表进行排序。因此，根据您的需要获取信息，并在Python中对其进行排序。