#21612: queryset update ignores to_field on foreign keys
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Reporter: berndtj@… | Owner: nobody
Type: Uncategorized | Status: new
Component: Uncategorized | Version: 1.5
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
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When issuing a batch update on a queryset, the to_field of the related
model is ignored in some cases. For instance, I am using a uuid field as
a foreign key field (to_field). When I try to update the relationship,
the pk is used for in the foreign key column (<foreign_model>_id) instead
of the uuid. For example given a queryset of BracketVolumeTemplates which
have a parent field which refers to a BracketVolume:
{{{
# The field definition
parent = models.ForeignKey(
'BracketVolume', null=True, blank=True, to_field='uuid',
related_name='parent_templates')
# We start with a queryset of one which has a BracketVolumeTemplate which
refers to a BracketVolume via the parent filed
ipdb> queryset
[<BracketVolumeTemplate [snapshot based] ID:
10dc67d94f8347d195e25eca6f3c22bb - created by [email protected]>]
ipdb> queryset[0].parent
<BracketVolume [snapshot] Requested State: DELETED ID:
2de07185d9744fdd83b5f683dfe5a2aa - created by [email protected]>
# The parent_id is correctly set as the UUID
ipdb> queryset[0].parent_id
u'2de07185d9744fdd83b5f683dfe5a2aa'
# We are updating with the kwargs as follows
ipdb> kwargs
{'parent': <BracketVolume [snapshot] Requested State: AVAILABLE ID:
62b72525425b4252925ba9ce48d42428 - created by [email protected]>}
ipdb> queryset.update(**kwargs)
1
# Wait, parent_id should be the UUID, but instead the pk is used for the
foreign key
ipdb> queryset[0].parent_id
u'3'
# Now the relationship is broken
ipdb> queryset[0].parent
*** DoesNotExist: BracketVolume matching query does not exist. Lookup
parameters were {'uuid__exact': u'3'}
# Queryset hides the db_columns, so we can't work around directly
ipdb> queryset.update(parent_id='2de07185d9744fdd83b5f683dfe5a2aa')
*** FieldDoesNotExist: BracketVolumeTemplate has no field named
'parent_id'
# The below workaround does work...
ipdb> queryset.update(parent='2de07185d9744fdd83b5f683dfe5a2aa')
1
ipdb> queryset[0].parent
<BracketVolume [snapshot] Requested State: DELETED ID:
2de07185d9744fdd83b5f683dfe5a2aa - created by [email protected]>
ipdb> c
}}}
I can work around this by adding the following code in my update code, but
it's not ideal:
{{{
for key in kwargs:
field = queryset.model._meta.get_field(key)
if isinstance(field, ForeignKey):
model = kwargs[key]
if not model:
continue
rel_att = field.rel.field_name
kwargs[key] = getattr(model, rel_att)
queryset.update(modified_by=modified_by_id, **kwargs)
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/21612>
Django <https://code.djangoproject.com/>
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