> Is there a better way to check if there are any hits on a query than
> using query.count()>0 ?
>
> I find myself doing something like this a lot:
> modelList = MyModel.objects.filter(someMember=m)
> if modelList.count() > 0:
> return modelList[0]
This sounds an awful lot like the .get() method of your objects[1]:
try:
return MyModel.objects.get(someMember=m)
except (MyModel.ObjectDoesNotExist, AssertionError):
do_something_else()
There's even a helper function[2] which can make this cleaner:
from django.shortcuts import get_object_or_404
get_object_or_404(MyModel, someMember=m)
assuming a 404 is what you want. But you can look at the source
as it's just python.
In terms of saving a query, you can use the "it's better to ask
forgiveness than permission" instead of "look before you leap".
The .get() method simply tries to request the objects[0] and if
it fails, an exception is raised...no need for the superfluous
count() call/query to "look before you leap". That means your
original code can just be written as
modelList = MyModel.objects.filter(someMember=m)
try:
return modelList[0]
except IndexError:
do_something_else()
-tim
[1]
http://www.djangoproject.com/documentation/db-api/#get-kwargs
[2]
http://www.djangoproject.com/documentation/shortcuts/#get-object-or-404
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