Django removing object from ManyToMany relationship

Question

How would I delete an object from a Many-to-Many relationship without removing the actual object?

Example:

I have the models Moods and Interest.

Mood has a many-to-many field interests (which is a models.ManyToManyField(Interest)).

I create an instance of Moods called my_mood. In my_moods's interests field I have my_interest, meaning

>>> my_mood.interests.all()
[my_interest, ...]

How do I remove my_interest from my_mood without deleting either model instance? In other words, how do I remove the relationship without affecting the related models?

score 287 · Accepted Answer · edited Feb 26 '20 at 20:34

287

my_mood.interests.remove(my_interest)

Django's Relations Docs

Note: you might have to get an instance of my_mood and my_interest using Django's QuerySet API before you can execute this code.

edited Feb 26 '20 at 20:34

Cory Madden

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answered Jun 13 '11 at 16:20

DrTyrsa

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`AttributeError: 'RelatedManager' object has no attribute 'remove'` – Cerin May 02 '17 at 18:11
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to add another `entry my_mood.interests.add(my_interest)` – Zohab Ali Aug 29 '18 at 08:18
@Cerin: (sorry for bumping an old comment) The question is about m2m, which implies a `ManyRelatedManager`, not a `RelatedManager`. That explains the `AttributeError`. – djvg Dec 14 '21 at 17:13
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Note that [ManyRelatedManager.remove()](https://github.com/django/django/blob/stable/4.0.x/django/db/models/fields/related_descriptors.py#L964) also accepts object `id`s. – djvg Dec 14 '21 at 17:13
don't forget to call `my_mood.save()` – Prasen Mar 09 '22 at 06:17
You can remove a list or queryset like this: `my_mood.interests.remove(*interest_queryset)` – Viet Pm Mar 08 '23 at 10:32

shacker · Answer 2 · 2019-04-09T20:47:33.440

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If you need to remove all M2M references without touching the underlying objects, it's easier to work from the other direction:

interest.mood_set.clear()

While this does not directly address the OP's question, it's often useful in this situation.

edited Apr 09 '19 at 20:47

answered May 05 '17 at 06:50

shacker

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Why was this downvoted? Granted it does not specifically address the OP's question, but I left the answer because it is of specific interest to people grappling with removing relations in M2M contexts, and removes the need to loop through instances. I thought it was a helpful related tip. – shacker Aug 16 '17 at 18:16
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This was just useful to me (I was about to loop through and didn't want to). Thanks for posting it! – bwv549 Nov 09 '17 at 22:01
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it could be better if you just add this point in above answer – brainLoop Oct 05 '18 at 13:13
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Or with related name in models and `interest.relatedname.clear()` – Josh Aug 05 '19 at 08:33

score 23 · Answer 3 · answered Dec 15 '17 at 06:18

23

In your case you can simply clear the relationship

my_mood.interests.clear()

Then perhaps when you are again creating new relation in your serializer you can do something like this

interests = Interests.objects.get_or_create(name='Something')
my_mood_obj.tags.add(tag[0])
my_mood_obj.save()

answered Dec 15 '17 at 06:18

Sabyasachi

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Since add immediately affects the database, you do not need to save afterwards ;) – cwhisperer Sep 11 '20 at 09:27

score -1 · Answer 4 · answered May 04 '21 at 10:35

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model.field.remove(object_you_want_to_remove)
In this case use: my_mood.interests.remove(my_interest)

answered May 04 '21 at 10:35

Himaloy Mondal

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simple duplicate of the correct answer. – xtlc Feb 17 '22 at 13:04

Django removing object from ManyToMany relationship

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