Python django.db.models 模块，Exists() 实例源码
我们从Python开源项目中，提取了以下12个代码示例，用于说明如何使用django.db.models.Exists()。
def get_activity(self, limit=20, offset=0, distinct=False, friends_only=False, request=None):
#Todo: make distinct work; combine friends and following,but then get posts from them
friends = Friendship.get_friendships(self, 0)
friend_ids = []
for friend in friends:
friend_ids.append(friend.other(self))
follows = self.follow_source.filter().values_list('target', flat=True)
if not friends_only:
friend_ids.append(self.id)
for thing in follows:
friend_ids.append(thing)
if request.user.is_authenticated:
has_yeah = Yeah.objects.filter(post=OuterRef('id'), by=request.user.id)
if distinct:
posts = Post.objects.select_related('creator').select_related('community').annotate(num_yeahs=Count('yeah', distinct=True), num_comments=Count('comment', yeah_given=Exists(has_yeah, distinct=True)).annotate(max_created=Max('creator__post__created')).filter(created=F('max_created')).filter(creator__in=friend_ids).order_by('-created')[offset:offset + limit]
else:
posts = Post.objects.select_related('creator').select_related('community').annotate(num_yeahs=Count('yeah', distinct=True)).filter(creator__in=friend_ids).order_by('-created')[offset:offset + limit]
if request:
for post in posts:
post.setup(request)
post.recent_comment = post.recent_comment()
return posts
def Feeds(username):
follower_ids = Relationship.objects.filter(
owner__user__username=username).values_list('follow_id', flat=True).distinct()
qs_reacted = Reaction.objects.filter(post=models.OuterRef('pk'),
owner__user__username=username)
qs_added = Post.objects.filter(origin=models.OuterRef('pk'),
owner__user__username=username)
return Post.objects.filter(
models.Q(owner_id__in=follower_ids) |
models.Q(owner__user__username=username)).annotate(
is_reacted=models.Exists(queryset=qs_reacted)).annotate(
is_added=models.Exists(queryset=qs_added)).order_by('-created_at')
def links_by_user(username, user=None):
qs_reactions = Reaction.objects.filter(post=models.OuterRef('pk'), owner=user)
qs_added = Post.objects.filter(origin=models.OuterRef('pk'), owner=user)
return Post.objects.filter(owner__user__username=username).annotate(
is_reacted=models.Exists(queryset=qs_reactions)).annotate(
is_added=models.Exists(queryset=qs_added)).order_by('-created_at')
def _with_has_successful_render_annotation(self):
renders = Render.objects.filter(paper=models.OuterRef('pk'),
state=Render.STATE_SUCCESS)
return self.annotate(has_successful_render=models.Exists(renders))
def _with_has_not_expired_render_annotation(self):
renders = Render.objects.filter(paper=models.OuterRef('pk'),
is_expired=False)
return self.annotate(has_not_expired_render=models.Exists(renders))
def get_queryset(self, *args, **kwargs):
overridden_reviews = Review.objects.filter(override_Vote__isnull=False, submission_id=models.OuterRef('pk'))
return self.request.event.submissions\
.order_by('review_id')\
.annotate(has_override=models.Exists(overridden_reviews))\
.annotate(avg_score=models.Case(
models.When(
has_override=True,
then=self.request.event.settings.review_max_score + 1,
),
default=models.Avg('reviews__score')
))\
.order_by('-state', '-avg_score')
def post_view(request, post):
has_yeah = Yeah.objects.filter(post=OuterRef('id'), by=request.user.id)
try:
post = Post.objects.annotate(num_yeahs=Count('yeah', distinct=True)).get(id=post)
except Post.DoesNotExist:
raise Http404()
post.setup(request)
if post.poll:
post.poll.setup(request.user)
if request.user.is_authenticated:
post.can_rm = post.can_rm(request)
post.is_favorite = post.is_favorite(request.user)
post.can_comment = post.can_comment(request)
if post.is_mine:
title = 'Your post'
else:
title = '{0}\'s post'.format(post.creator.nickname)
all_comment_count = post.number_comments()
if all_comment_count > 20:
comments = post.get_comments(request, None, all_comment_count - 20)
else:
comments = post.get_comments(request)
return render(request, 'closedverse_main/post-view.html', {
'title': title,
#CSS might not be that friendly with this / 'classes': ['post-permlink'],
'post': post,
'yeahs': post.get_yeahs(request),
'comments': comments,
'all_comment_count': all_comment_count,
'ogdata': {
'title': title,
'description': post.trun(),
'date': str(post.created),
'image': post.creator.do_avatar(post.feeling),
},
})
def get_posts(self, limit=50, request=None):
if request.user.is_authenticated:
has_yeah = Yeah.objects.filter(post=OuterRef('id'), by=request.user.id)
posts = self.post_set.select_related('community').select_related('creator').annotate(num_yeahs=Count('yeah', distinct=True)).filter().order_by('-created')[offset:offset + limit]
else:
posts = self.post_set.select_related('community').select_related('creator').annotate(num_yeahs=Count('yeah', distinct=True)).filter().order_by('-created')[offset:offset + limit]
if request:
for post in posts:
post.setup(request)
post.recent_comment = post.recent_comment()
return posts
def get_comments(self, request=None):
if request.user.is_authenticated:
has_yeah = Yeah.objects.filter(comment=OuterRef('id'), by=request.user.id)
posts = self.comment_set.select_related('original_post').select_related('creator').select_related('original_post__creator').annotate(num_yeahs=Count('yeah', distinct=True)).filter().order_by('-created')[offset:offset + limit]
else:
posts = self.comment_set.select_related('original_post').select_related('original_post__creator').select_related('creator').annotate(num_yeahs=Count('yeah', distinct=True)).filter().order_by('-created')[offset:offset + limit]
if request:
for post in posts:
post.setup(request)
return posts
def get_posts(self, request=None, favorite=False):
if request.user.is_authenticated:
has_yeah = Yeah.objects.filter(post=OuterRef('id'), by=request.user.id)
posts = Post.objects.select_related('creator').annotate(num_yeahs=Count('yeah', distinct=True)).filter(community_id=self.id).order_by('-created')[offset:offset + limit]
else:
posts = Post.objects.select_related('creator').annotate(num_yeahs=Count('yeah', distinct=True)).filter(community_id=self.id).order_by('-created')[offset:offset + limit]
if request:
for post in posts:
post.setup(request)
post.recent_comment = post.recent_comment()
return posts
def get_queryset(self):
queryset = super().get_queryset()
queryset = queryset.filter(public=True)
queryset = queryset.annotate(
has_docnode=Exists(DocNode.objects.filter(
policy=OuterRef('pk'),
)),
total_reqs=relevant_reqs_count({}),
relevant_reqs=relevant_reqs_count(self.request.GET),
).filter(relevant_reqs__gt=0)
return queryset
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