为什么queryset返回值而不是Django视图中的实例？
为什么queryset返回值而不是Django视图中的实例？
提问于 2022-09-01 14:16:27
我的问题
我在Django视图有个查询集。该查询集应该返回一个实例。但是它不会返回一个值。
Models.py
class Author(models.Model):
name = models.CharField(max_length=250, unique=True)
def __str__(self):
return self.name
def get_absolute_url(self):
return reverse('authors:author_detail', args=[str(self.id)])
class Meta:
verbose_name = 'Author'
verbose_name_plural = 'Authors'项目URLS.py
urlpatterns = [
path('admin/', admin.site.urls),
path('author/', include('authors_app.urls', namespace='authors')),
]authors_app ULRS.py
from .views import *
app_name = 'authors'
urlpatterns = [
path('<int:pk>/', AuthorDetail.as_view(), name='author_detail'),
]Views.py
class AuthorDetail(ListView):
model = Book
context_object_name = 'author_books'
template_name = 'author-detail.html'
queryset = Book.objects.all().order_by('bookinfo__bestseller')
paginate_by = 36
def get_queryset(self, **kwargs):
author_id = Author.objects.get(pk = self.kwargs['pk'])
print(author_id)
qs = super().get_queryset(**kwargs)
return qs.filter(author = author_id)
def get_context_data(self, **kwargs):
# Call the base implementation first to get a context
context = super().get_context_data(**kwargs)
# Add in a QuerySet
context['author'] = Author.objects.get(pk = self.kwargs['pk'])
# context['image'] = f"/mnt/HDD/wiki/parser/images/photos/10.png"
return context溯源
Traceback (most recent call last):
File "/mnt/HDD/tibrains.test/titest-env/lib/python3.8/site-packages/django/core/handlers/exception.py", line 47, in inner
response = get_response(request)
File "/mnt/HDD/tibrains.test/titest-env/lib/python3.8/site-packages/django/core/handlers/base.py", line 181, in _get_response
response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "/mnt/HDD/tibrains.test/titest-env/lib/python3.8/site-packages/django/views/generic/base.py", line 70, in view
return self.dispatch(request, *args, **kwargs)
File "/mnt/HDD/tibrains.test/titest-env/lib/python3.8/site-packages/django/views/generic/base.py", line 98, in dispatch
return handler(request, *args, **kwargs)
File "/mnt/HDD/tibrains.test/titest-env/lib/python3.8/site-packages/django/views/generic/list.py", line 142, in get
self.object_list = self.get_queryset()
File "/mnt/HDD/tibrains/08/titest_project/authors_app/views.py", line 17, in get_queryset
return qs.filter(author = author_id)
File "/mnt/HDD/tibrains.test/titest-env/lib/python3.8/site-packages/django/db/models/query.py", line 941, in filter
return self._filter_or_exclude(False, args, kwargs)
File "/mnt/HDD/tibrains.test/titest-env/lib/python3.8/site-packages/django/db/models/query.py", line 961, in _filter_or_exclude
clone._filter_or_exclude_inplace(negate, args, kwargs)
File "/mnt/HDD/tibrains.test/titest-env/lib/python3.8/site-packages/django/db/models/query.py", line 968, in _filter_or_exclude_inplace
self._query.add_q(Q(*args, **kwargs))
File "/mnt/HDD/tibrains.test/titest-env/lib/python3.8/site-packages/django/db/models/sql/query.py", line 1393, in add_q
clause, _ = self._add_q(q_object, self.used_aliases)
File "/mnt/HDD/tibrains.test/titest-env/lib/python3.8/site-packages/django/db/models/sql/query.py", line 1412, in _add_q
child_clause, needed_inner = self.build_filter(
File "/mnt/HDD/tibrains.test/titest-env/lib/python3.8/site-packages/django/db/models/sql/query.py", line 1320, in build_filter
self.check_related_objects(join_info.final_field, value, join_info.opts)
File "/mnt/HDD/tibrains.test/titest-env/lib/python3.8/site-packages/django/db/models/sql/query.py", line 1147, in check_related_objects
self.check_query_object_type(value, opts, field)
File "/mnt/HDD/tibrains.test/titest-env/lib/python3.8/site-packages/django/db/models/sql/query.py", line 1128, in check_query_object_type
raise ValueError(
ValueError: Cannot query "Lawrence Gilman": Must be "Author" instance.当我打开作者页面- mysite.com/author/51/时，我发现了一个错误:无法查询"Lawrence“：必须是"Author”实例。
问题
我如何在查询集中获得一个实例？
回答 2
Stack Overflow用户
回答已采纳
发布于 2022-09-01 19:31:36
您可以使用author_id本身进行筛选，从而获得具有以下内容的get_queryset：
from django.shortcuts import get_object_or_404
class AuthorDetailView(ListView):
# …
def get_queryset(self, **kwargs):
return super().get_queryset(**kwargs).filter(author_id=self.kwargs['pk'])
def get_context_data(self, **kwargs):
return super().get_context_data(
**kwargs, author=get_object_or_404(Author, pk=self.kwargs['pk'])
)Stack Overflow用户
发布于 2022-09-01 14:51:38
我想这就是问题所在：
author_id = Author.objects.get(pk = self.kwargs['pk'])使用filter而不是get
author_id = Author.objects.filter(pk = self.kwargs['pk'])页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/73570884
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