Not possible to update foreign key by id for a queryset

[dakinsloss@…]

Attempting to minimize queries when updating list of ModelA instances that have foreign keys to ModelB, and I know the ids of the new ModelB instances I want to use for the instances of ModelA (that I only have the id for, not the instance).

Trying:
ModelA.objects.filter(pk=id_of_a_instance).update(b_id=id_of_b_instance) which yields 'FieldNameDoesNotExist' because 'get_field_by_name' only has 'b' as a field name for ModelA, not b_id (which is strange given that is what is actually stored).

Then I try:
ModelA.objects.filter(pk=id_of_a_instance).update(b=id_of_b_instance), which says it needs an instance of ModelB, not a number.

Which means I will be stuck with an extra query:
model_b_list = list(ModelB.objects.filter(id_in=[list of ids for a instances])
and then have to iterate through the ModelA instances and assign the actual ModelB instances

[dakinsloss@…]

My mistake--this should not have been submitted, was still debugging and this is not an issue.

[mbhagya@…]

Sorry but what happened to this bug? Is this fixed in a later version? Because I can still see this in 1.5.

[Anthony Lalande]

Could I ask for additional clarifications regarding why this issue was closed and set to invalid? This seems like a legitimate use case to support, no?

[Carl Meyer]

Looks like the original reporter closed it without much explanation. I'm reopening, because I agree this is a valid case and should be supported somehow (I think probably by accepting raw IDs for an FK field in update).

[vaskalas]

Issue was fixed in commit c21e86ab9e3e5ebd6d245d038cb0cb352cd84c3a. Added unit tests to verify fix in ​https://github.com/django/django/pull/4499

[vaskalas]

The unit test was added actually added in this commit, ​https://github.com/django/django/commit/e01b5a5823fa06a63382f87472978a16c77048d2