40👍
I think you got it right on the money, except you don’t need to convert to a list.
source.items.remove(*source.items.filter(*args))
The remove
/add
method looks like the following
remove(self, *objs)
add(self, *objs)
and the docs use add multiple examples in the form of [p1, p2, p3]
so I’d wager the same goes for remove
, seeing as the arguments are the same.
>>> a2.publications.add(p1, p2, p3)
Digging in a little more, the remove function iterates over *objs
one by one, checking if it’s of the valid model, otherwise using the values as PK’s, then deletes the items with a pk__in
, so I’m gonna say yes, the best way is to query your m2m table first for objects to delete then pass in those objects into the m2m manager.
# django.db.models.related.py
def _remove_items(self, source_field_name, target_field_name, *objs):
# source_col_name: the PK colname in join_table for the source object
# target_col_name: the PK colname in join_table for the target object
# *objs - objects to remove
# If there aren't any objects, there is nothing to do.
if objs:
# Check that all the objects are of the right type
old_ids = set()
for obj in objs:
if isinstance(obj, self.model):
old_ids.add(obj.pk)
else:
old_ids.add(obj)
if self.reverse or source_field_name == self.source_field_name:
# Don't send the signal when we are deleting the
# duplicate data row for symmetrical reverse entries.
signals.m2m_changed.send(sender=rel.through, action="pre_remove",
instance=self.instance, reverse=self.reverse,
model=self.model, pk_set=old_ids)
# Remove the specified objects from the join table
db = router.db_for_write(self.through.__class__, instance=self.instance)
self.through._default_manager.using(db).filter(**{
source_field_name: self._pk_val,
'%s__in' % target_field_name: old_ids
}).delete()
if self.reverse or source_field_name == self.source_field_name:
# Don't send the signal when we are deleting the
# duplicate data row for symmetrical reverse entries.
signals.m2m_changed.send(sender=rel.through, action="post_remove",
instance=self.instance, reverse=self.reverse,
model=self.model, pk_set=old_ids)
15👍
According to current docs there is a through
property that gives you an access to table that manages many-to-many relation, like so Model.m2mfield.through.objects.all()
So in terms of your example:
source.items.through.objects \
.filter(item__timestamp__lte=some_datetime) \
.delete()
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