ich ein User-Modell habe, kann jeder Benutzer viel Post von diesem relateion haben:Django mit Anmerkungen versehen auf Prefetch gefiltert verwandtes Modell
class Post(models.Model):
...
user = models.ForeignKey('User', related_name='posts')
, und jeder Pfosten eine like_count (Integer-Feld), ich mag Benutzer erhalten (entlang ihrer Beiträge), die mehr als n Stellen hat, die mehr als m mal gemocht, ich tue:
User.objects.prefetch_related(Prefetch('posts', queryset=Post.objects.filter(like_count__gte=m), to_attr='top_posts')).annotate(top_post_count=Count('top_posts')).filter(top_post_count__gte=n)
aber, bekomme ich:
Traceback (most recent call last):
File "<console>", line 1, in <module>
File "/usr/local/lib/python3.4/dist-packages/django/db/models/query.py", line 912, in annotate
clone.query.add_annotation(annotation, alias, is_summary=False)
File "/usr/local/lib/python3.4/dist-packages/django/db/models/sql/query.py", line 971, in add_annotation
summarize=is_summary)
File "/usr/local/lib/python3.4/dist-packages/django/db/models/aggregates.py", line 19, in resolve_expression
c = super(Aggregate, self).resolve_expression(query, allow_joins, reuse, summarize)
File "/usr/local/lib/python3.4/dist-packages/django/db/models/expressions.py", line 513, in resolve_expression
c.source_expressions[pos] = arg.resolve_expression(query, allow_joins, reuse, summarize, for_save)
File "/usr/local/lib/python3.4/dist-packages/django/db/models/expressions.py", line 463, in resolve_expression
return query.resolve_ref(self.name, allow_joins, reuse, summarize)
File "/usr/local/lib/python3.4/dist-packages/django/db/models/sql/query.py", line 1462, in resolve_ref
self.get_initial_alias(), reuse)
File "/usr/local/lib/python3.4/dist-packages/django/db/models/sql/query.py", line 1402, in setup_joins
names, opts, allow_many, fail_on_missing=True)
File "/usr/local/lib/python3.4/dist-packages/django/db/models/sql/query.py", line 1327, in names_to_path
"Choices are: %s" % (name, ", ".join(available)))
django.core.exceptions.FieldError: Cannot resolve keyword 'top_posts' into field. Choices are: ...
Post vollständige Rückverfolgung des Fehlers und Ihre models.py – kt14
@ kt14 Beitrag aktualisiert – Mohsen
Diese Annotation-Methode funktioniert in Django 2.0. Du hast mein Leben gerettet. Ich bin ewig dankbar. –