Python Django反向查找外键
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Django reverse lookup of foreign keys
提问by FLX
I have a venue, this venue has many events happening there. My models look like this:
我有一个场地，这个场地有很多活动在那里发生。我的模型看起来像这样：
class Event(models.Model):
title = models.CharField(max_length=200)
date_published = models.DateTimeField('published date',default=datetime.now, blank=True)
date_start = models.DateTimeField('start date')
date_end = models.DateTimeField('end date')
def __unicode__(self):
return self.title
description = models.TextField()
price = models.IntegerField(null=True, blank=True)
venue = models.ForeignKey(Venue)
class Venue(models.Model):
title = models.CharField(max_length=200)
date_published = models.DateTimeField('published date',default=datetime.now, blank=True)
venue_latitude = models.CharField(max_length=200)
venue_longitude = models.CharField(max_length=200)
venue_address = models.CharField(max_length=200)
venue_city = models.CharField(max_length=200)
venue_state = models.CharField(max_length=200)
venue_country = models.CharField(max_length=200)
description = models.TextField()
def __unicode__(self):
return u'%s' % (self.title)
I'd like to display all the events that are happening at a certain venue. How can I do that? My current view looks like:
我想显示在某个地点发生的所有事件。我怎样才能做到这一点？我目前的观点是这样的：
def detail(request, venue_id):
venue = get_object_or_404(Venue, pk=venue_id)
return render(request, 'venue-detail.html', {'venue': venue})
采纳答案by Ric
You can use events = venue.event_setto go the other way.
你可以用events = venue.event_set另一条路。
Note that venue.event_setis a manager object, like Event.objects, so you can call .all, .filter, .excludeand similar on it to get a queryset.
请注意，venue.event_set是经理的对象，像Event.objects，这样你就可以打电话.all，.filter，.exclude和类似它来得到一个查询集。
See the Django documentation
回答by rjv
Go the other way round. Use Eventmodel.
走另一条路。使用Event模型。
def detail(request, venue_id):
venue = Event.objects.filter(venue__id=venue_id)
return render(request, 'venue-detail.html', {'venue': venue})
PS: I have never used get_object_or_404(). Modify code accordingly.
PS：我没用过get_object_or_404()。相应地修改代码。
回答by Apex
To those who have "'RelatedManager' object is not iterable"
对于那些拥有“'RelatedManager' 对象不可迭代”的人
Add all to retrieve the elements from the manager.
添加 all 以从管理器中检索元素。
{% for area in world_areas.all %}
https://stackoverflow.com/a/16909142/2491526(cannot add this in comment to the first answer)
https://stackoverflow.com/a/16909142/2491526（不能在评论中添加到第一个答案）
