On 12/18/06, Waylan Limberg <[EMAIL PROTECTED]> wrote:
>
> On 12/18/06, Gary Wilson <[EMAIL PROTECTED]> wrote:
> >
> > I often find myself writing code like:
> >
> > try:
> > user = User.objects.get(pk=user_id)
> > except User.DoesNotExist:
> > user = None
> >
> > What do you think about adding a get_or_none QuerySet method?
> >
> > def get_or_none(self, **kwargs):
> > try:
> > return self.get(**kwargs)
> > except self.model.DoesNotExist:
> > return None
> >
>
> Or how about using something similar to QuearyDict's get(key,
> default)? That way the fallback is not restricted to `None`. So
> something like this:
>
> user = User.objects.get(pk=user_id, default=None)
>
> Of course, I think that would probably be significantly more work than
> your little wrapper function.
note neccessarily (beware, quick&ugly proof of concept):
Index: django/db/models/query.py
===================================================================
--- django/db/models/query.py (revision 4227)
+++ django/db/models/query.py (working copy)
@@ -12,6 +12,8 @@
# The string constant used to separate query parts
LOOKUP_SEPARATOR = '__'
+# for get(default)
+NOT_SET='WHATEVER'
# The list of valid query types
QUERY_TERMS = (
@@ -202,7 +204,8 @@
cursor.execute("SELECT COUNT(*)" + sql, params)
return cursor.fetchone()[0]
- def get(self, *args, **kwargs):
+
+ def get(self, default=NOT_SET, *args, **kwargs):
"Performs the SELECT and returns a single object matching the
given keyword arguments."
clone = self.filter(*args, **kwargs)
# clean up SQL by removing unneeded ORDER BY
@@ -210,6 +213,8 @@
clone._order_by = ()
obj_list = list(clone)
if len(obj_list) < 1:
+ if default != NOT_SET:
+ return default
raise self.model.DoesNotExist, "%s matching query does
not exist." % self.model._meta.object_name
assert len(obj_list) == 1, "get() returned more than one %s
-- it returned %s! Lookup parameters were %s" %
(self.model._meta.object_name, len(obj_list), kwargs)
return obj_list[0]
> --
> ----
> Waylan Limberg
> [EMAIL PROTECTED]
>
> >
>
--
Honza Král
E-Mail: [EMAIL PROTECTED]
ICQ#: 107471613
Phone: +420 606 678585
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