Opened 7 years ago

Closed 7 years ago

Last modified 5 years ago

#12859 closed (fixed)

Incorrect docs on Updating multiple objects at once using related records

Reported by: Derek Willis Owned by: Derek Willis
Component: Documentation Version: 1.0
Severity: Keywords:
Cc: Triage Stage: Ready for checkin
Has patch: yes Needs documentation: no
Needs tests: no Patch needs improvement: no
Easy pickings: UI/UX:

Description

The docs for Updating multiple objects at once say that "The only restriction on the QuerySet that is updated is that it can only access one database table, the model's main table. So don't try to filter based on related fields or anything like that; it won't work."

But I've been able to update a QuerySet based on a filter of related records. You just can't update the related records. For example, given the following models:

class CoachingJob(models.Model):
    name = models.CharField(max_length=75)
    slug = models.SlugField(max_length=75)

class CollegeCoach(models.Model):
    coach = models.CharField(max_length=75)
    jobs = models.ManyToManyField(CoachingJob)
    start_date = models.DateField(null=True, blank=True)
    end_date = models.DateField(null=True, blank=True)
    is_head_coach = models.BooleanField(default=False)

I can perform the following update successfully:

CollegeCoach.objects.select_related().filter(jobs__name='Head Coach').update(is_head_coach=True) 

If I try to update the CoachingJob model, it properly raises a FieldDoesNotExist error:

CollegeCoach.objects.select_related().filter(jobs__name='Head Coach').update(jobs__name='Top Dog')

FieldDoesNotExist: CollegeCoach has no field named 'name' 

The attached patch suggests changing the docs to say that filtering on related records is permitted, but not updating those related records, and provides an example.

Attachments (2)

12859.patch (1.3 KB) - added by Derek Willis 7 years ago.
12859.2.patch (1.3 KB) - added by Tim Graham 7 years ago.
tabs -> spaces for existing patch

Download all attachments as: .zip

Change History (8)

Changed 7 years ago by Derek Willis

Attachment: 12859.patch added

comment:1 Changed 7 years ago by Derek Willis

Has patch: set
Needs documentation: unset
Needs tests: unset
Patch needs improvement: unset
Status: newassigned

comment:2 Changed 7 years ago by Russell Keith-Magee

milestone: 1.2
Triage Stage: UnreviewedAccepted

Changed 7 years ago by Tim Graham

Attachment: 12859.2.patch added

tabs -> spaces for existing patch

comment:3 Changed 7 years ago by Tim Graham

Triage Stage: AcceptedReady for checkin

comment:4 Changed 7 years ago by Russell Keith-Magee

Resolution: fixed
Status: assignedclosed

(In [12515]) Fixed #12859 -- Clarified the documentation on using multiple tables with .update() calls. Thanks to dwillis for the report.

comment:5 Changed 7 years ago by Russell Keith-Magee

(In [12520]) [1.1.X] Fixed #12859 -- Clarified the documentation on using multiple tables with .update() calls. Thanks to dwillis for the report.

Backport of r12515 from trunk.

comment:6 Changed 5 years ago by Jacob

milestone: 1.2

Milestone 1.2 deleted

Note: See TracTickets for help on using tickets.
Back to Top