#28344: Add for_update parameter to Model.refresh_from_db()
-------------------------------------+-------------------------------------
Reporter: Patryk Zawadzki | Owner: (none)
Type: New feature | Status: new
Component: Database layer | Version: dev
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Comment (by Simon Charette):
I don't think it would be a problem for `refresh_from_db` to apply fields
and `using` if explicitly provided with `from_queryset`
{{{#!diff
diff --git a/django/db/models/base.py b/django/db/models/base.py
index 6eaa600f10..8a9cbd606e 100644
--- a/django/db/models/base.py
+++ b/django/db/models/base.py
@@ -672,7 +672,7 @@ def get_deferred_fields(self):
if f.attname not in self.__dict__
}
- def refresh_from_db(self, using=None, fields=None):
+ def refresh_from_db(self, using=None, fields=None,
from_queryset=None):
"""
Reload field values from the database.
@@ -704,10 +704,15 @@ def refresh_from_db(self, using=None, fields=None):
"are not allowed in fields." % LOOKUP_SEP
)
- hints = {"instance": self}
- db_instance_qs = self.__class__._base_manager.db_manager(
- using, hints=hints
- ).filter(pk=self.pk)
+ if from_queryset is not None:
+ if using is not None:
+ from_queryset = from_queryset.using(using)
+ else:
+ hints = {"instance": self}
+ from_queryset = self.__class__._base_manager.db_manager(
+ using, hints=hints
+ )
+ db_instance_qs = from_queryset.filter(pk=self.pk)
# Use provided fields, if not set then reload all non-deferred
fields.
deferred_fields = self.get_deferred_fields()
}}}
That would mean that
{{{#!python
refresh_from_db(using='other',
from_queryset=Author.objects.using('default')) # would use `other`
refresh_from_db(fields=['first_name'],
from_queryset=Author.objects.only('last_name')) # would use ['first_name']
Why do you think the addition of a `refresh_from_queryset` method is
warranted?
--
Ticket URL: <https://code.djangoproject.com/ticket/28344#comment:33>
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