Question

我在django中有3个模型：

class Movie(models.Model):
    mid = models.IntegerField(primary_key = True)
    name = models.CharField(max_length = 100)

class User(models.Model):
    username = models.CharField(max_length=128, null=True)
    uid = models.CharField(max_length=100)
    movie = models.ManyToManyField(Movie, through = "Vote")

class Vote(models.Model):
    movie = models.ForeignKey(Movie)
    user = models.ForeignKey(User)
    rating = models.IntegerField()

这里评级= 0 / 1,0表示不喜欢，1表示喜欢我想使用过滤器进行一些查询：

找出当前用户喜欢的所有电影。为此，我使用以下2个查询，但它们都不起作用。在这两种情况下，它都会产生错误的结果

ans = Movie.objects.filter(vote__user = self).filter(vote__rating = 1)

ans = Movie.objects.filter(user__uid = self.uid).filter(vote__rating = 1)
我有一个数组 ID 的用户列表。我想知道这个列表中有多少用户喜欢特定的电影？我试过这个，但这也是不正确的：

ret = User.objects.filter(uid__in = ids).filter(vote__movie = mov).filter(vote__rating = 1)

有人可以帮我解决这两个问题吗？

Answer 1

我还建议让django分配模型的id，但是如果你使用遗留数据库或者由于某些其他原因需要分配id，你可以这样查询：

# uid is some uid
user = User.objects.get(uid=uid)
likes = Movie.objects.filter(vote__user=user, vote__rating=1)

或

likes = Movie.objects.filter(vote__user__uid=some_uid, vote__rating=1)

喜欢特定电影的用户列表中的人数：

>>> uids = ['1','2','3']
>>> # if mov is a Movie instance
>>> votes = Vote.objects.filter(user__uid__in=uids, movie=mov, rating=1)
>>> print votes.query
SELECT "so1_vote"."id", "so1_vote"."movie_id", "so1_vote"."user_id", "so1_vote"."rating" FROM "so1_vote" INNER JOIN "so1_user" ON ("so1_vote"."user_id" = "so1_user"."id") WHERE ("so1_user"."uid" IN (1, 2, 3) AND "so1_vote"."movie_id" = 1  AND "so1_vote"."rating" = 1 )
>>> # if mov is a mid for a movie
>>> # get movie instance by using Movie.objects.get(mid=mov)
>>> # or query:
>>> # votes = Vote.objects.filter(user__uid__in=uids, movie__mid=mov, rating=1)
>>> likes_count = votes.count()
>>> print likes_count
0

组合：

likes_count = Votes.objects.filter(user__uid__in=uids, movie=mov, rating=1).count()

Django查询使用过滤器

1 个答案: