Django concatenate a db object with empty QuerySet
I have created an empty QuerySet in django like this.
empty = classname.objects.none()
and I have an object of same class (called class).
cla开发者_Python百科ss
I want a new QuerySet having 'class' in it.
There is no append method on EmptyQuerySet and | and & do not work for the db object.
>>> empty = Person.objects.none()
if you use get you return a db object and get this error when you try use | to append the object to the empty qs:
>>> qs = empty|Person.objects.get(pk=1)
Traceback (most recent call last):
File "<console>", line 1, in <module>
File "/home/dev/.virtualenvs/dev/lib/python2.7/site-packages/django/db/models/query.py", line 1018, in __or__
return other._clone()
AttributeError: 'Person' object has no attribute '_clone'
however you can use the | operator to combine two query sets. To get the object as a query set we can use .filter():
>>> qs = empty|Person.objects.filter(pk=1)
>>> print qs
[<Person: A>]
>>> qs = qs|Person.objects.filter(pk=2)
>>> print qs
[<Person: A>, <Person: B>]
>>>
精彩评论