# \[Django Admin Customization\] Avoid Overwriting Fields When Multiple Users Edit the Same Object

**URL:** <https://forum.djangoproject.com/t/django-admin-customization-avoid-overwriting-fields-when-multiple-users-edit-the-same-object/36920>\
**Category:** The Admin\
**Created:** [December 3, 2024, 11:08am UTC](https://forum.djangoproject.com/t/django-admin-customization-avoid-overwriting-fields-when-multiple-users-edit-the-same-object/36920 "2024-12-03T11:08:45Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![ulr0](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.djangoproject.com/ulr0/32/25556_2.png) [@ulr0](https://forum.djangoproject.com/u/ulr0)\
**Post date:** [December 3, 2024, 11:08am UTC](https://forum.djangoproject.com/t/django-admin-customization-avoid-overwriting-fields-when-multiple-users-edit-the-same-object/36920/1 "2024-12-03T11:08:46Z")

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### Problem

When two staff users open the same admin change page and perform the following actions:

1. **User A** changes the `name` field from “test\_a” to “test\_b” and saves the object.
2. **User B** , without refreshing the page, updates the `price` field from 100 to 105 (with the `name` field still showing “test\_a”) and saves the object.

The result is that **User A’s changes to the `name` field (“test\_b”) are overwritten**. The final object becomes:

- `name`: “test\_a”
- `price`: 105

However, the expected result should be:

- `name`: “test\_b”
- `price`: 105

### Solution

To prevent this issue, I am planning to customize Django Admin’s **`ModelAdmin`** class to:

1. **On GET requests** : Store the current object state in Redis.
2. **On POST requests** : Use the state stored in Redis to update only the changed fields.

Below is a simplified example:

```auto
class CustomModelAdmin(ModelAdmin):
    def save_model(self, request, obj, form, change):
        if change:
            obj.save(update_fields=form.changed_data) # Save only updated fields
        else:
            super().save_model(request, obj, form, change)

    def change_view(self, request, object_id, form_url="", extra_context=None):
        if request.method == "GET":
            obj = self.get_object(request, object_id) # Get the current object
            if obj:
                cache_key = make_cache_key(object_id, request.user.id) # Create a cache key
                redis_client.set(cache_key, obj) # Store the object in Redis
        return super().change_view(request, object_id, form_url, extra_context)

    def get_object(self, request, object_id, from_field=None):
        if request.method == "POST":
            cache_key = make_cache_key(object_id, request.user.id)
            cached_data = redis_client.get(cache_key)
            if cached_data:
                return cached_data # Return the cached object
        return super().get_object(request, object_id, from_field)

```

Note: `make_cache_key` and `redis_client` are assumed to be defined elsewhere.

### Feedback Request

Has anyone tried a similar approach, or do you have thoughts on this idea?  
I’d appreciate any feedback or suggestions for improvement.

---

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**Author:** ![KenWhitesell](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.djangoproject.com/kenwhitesell/32/280_2.png) [@KenWhitesell](https://forum.djangoproject.com/u/KenWhitesell)\
**Post date:** [December 3, 2024, 1:50pm UTC](https://forum.djangoproject.com/t/django-admin-customization-avoid-overwriting-fields-when-multiple-users-edit-the-same-object/36920/2 "2024-12-03T13:50:47Z")

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This topic was previously discussed at [Automatically setting update\_fields when saving a model instance](https://forum.djangoproject.com/t/automatically-setting-update-fields-when-saving-a-model-instance/26798), which includes an explanation of a situation where this would _not_ be desirable outcome.

In fact, while I do acknowledge the problem of a “lost update”, that is actually _less_ problematic to me than inconsistent data generated as a result of an incomplete update.

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<div class="post-metadata">

**Author:** ![philgyford](https://sea2.discourse-cdn.com/flex026/user_avatar/forum.djangoproject.com/philgyford/32/14295_2.png) [@philgyford](https://forum.djangoproject.com/u/philgyford)\
**Post date:** [December 3, 2024, 4:11pm UTC](https://forum.djangoproject.com/t/django-admin-customization-avoid-overwriting-fields-when-multiple-users-edit-the-same-object/36920/3 "2024-12-03T16:11:49Z")

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A safer solution might be to ensure that only one person can edit an object at a time, or at least show a warning if it’s already being edited by someone.

I’m not saying I know how best to do this but it seems fairly common in CMS’s. e.g. I think Wagtail shows a warning, and I think WordPress shows a pop-up saying the page is already being edited, and if you want to take over.

A quick google suggests [Django Concurrency](https://django-concurrency.readthedocs.io/en/latest/index.html) might do this and it looks actively maintained.