[英]Django - Query by foreign key in views
我正在嘗試在帖子上制作一個按鈕,當用戶點擊它時,請求將其作為出席添加到帖子中,然后帖子的作者必須批准該請求。
模型.py
class Attending(models.Model):
is_approved = models.BooleanField(default=False)
attending = models.ManyToManyField(User, related_name='user_event_attending')
class Post(models.Model):
title = models.CharField(max_length=100)
content = models.TextField(blank=True)
date_posted = models.DateTimeField(default=timezone.now)
author = models.ForeignKey(User, on_delete=models.CASCADE)
attending = models.ForeignKey(Attending, on_delete=models.CASCADE, verbose_name='atending', null=True)
我的問題是,每次我為按鈕寫一個查詢時都會給我錯誤,我無法弄清楚如何獲得外鍵的反向。
這是我在views.py上的代碼
def request_event(request, pk):
previous = request.META.get('HTTP_REFERER')
try:
query = Attending.objects.get(pk=pk)
request_attending = query.post_set.add(request.user)
messages.success(request, f'Request sent!')
return redirect(previous)
except query.DoesNotExist:
return redirect('/')
非常感謝您的提前幫助!
這: query.post_set
只是關系。 您不能像那樣調用方法add
。 您可以添加到ManyToMany
關系,我相信您想將用戶添加到Attending.attending
字段,而不是直接添加到Post
object。將其更改為:
...
query = Attending.objects.get(pk=pk)
query.attending.add(request.user)
messages.success(request, f'Request sent!')
....
| 更新 |
我認為你應該考慮重新安排你的關系。 如果我了解你的計划,你應該這樣撥打 go:
class Attending(models.Model):
...
attendant = models.ForeignKey(User, related_name='events_attending', on_delete=models.CASCADE)
post = models.ForeignKey('Post', on_delete=models.CASCADE)
class Post(models.Model):
...
author = models.ForeignKey(User, on_delete=models.CASCADE)
對於一個Post
object 可以有多個Attending
對象,那么你可以使用這樣的關系:
att = Attending.objects.first()
att.post # get related Post object from ForeignKey | there is only one
post = Post.objects.first()
post.attending_set.all() # get all related Attending objects
Post.objects.get(attending=att) # get Post object that the Attending object have in ForeignKey field
user = User.objects.first()
user.post_set.all() # get all Post objects that User is author in
user.events_attending.all() # get all related Attending objects
有關更多信息,請查看Django 文檔。
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