Django loaddata UNIQUE 约束失败

Question

I'm running python manage.py loaddata 'path/to/mydata.json' with an empty database ( User and UserProfile tables are created but not populated), however, I'm getting the following error:

django.db.utils.IntegrityError: Problem installing fixture 'path/to/mydata.json': Could not load myapp.UserProfile(pk=1): UNIQUE constraint failed: myapp_userprofile.user_id

I checked (even after running this command) and the database is not populated at all. So how can it be giving an error that the pk is not unique?

If relevant, UserProfile just extends the default User model with a OneToOneField relation, as proposed here .

Here is what mydata.json contains:

[
    {
        "model": "auth.user",
        "pk": 1,
        "fields": {
            "password": "pbkdf2_sha256..",
            "last_login": "2016-10-22T15:19:46.926Z",
            "is_superuser": true,
            "username": "thesuperuser",
            "first_name": "",
            "last_name": "",
            "email": "a@a.co",
            "is_staff": true,
            "is_active": true,
            "date_joined": "2016-10-22T14:48:27.394Z",
            "groups": [],
            "user_permissions": []
        }
    },
    {
        "model": "auth.user",
        "pk": 2,
        "fields": {
            "password": "pbkdf2_sha256..",
            "last_login": null,
            "is_superuser": false,
            "username": "user1",
            "first_name": "User",
            "last_name": "One",
            "email": "",
            "is_staff": false,
            "is_active": true,
            "date_joined": "2016-10-22T15:20:32Z",
            "groups": [],
            "user_permissions": []
        }
    },
    {
        "model": "auth.user",
        "pk": 4,
        "fields": {
            "password": "pbkdf2_sha256..",
            "last_login": null,
            "is_superuser": false,
            "username": "user3",
            "first_name": "User",
            "last_name": "Three",
            "email": "",
            "is_staff": false,
            "is_active": true,
            "date_joined": "2016-10-22T15:21:09Z",
            "groups": [],
            "user_permissions": []
        }
    },
    {
        "model": "auth.user",
        "pk": 3,
        "fields": {
            "password": "pbkdf2_sha256..",
            "last_login": null,
            "is_superuser": false,
            "username": "user2",
            "first_name": "User",
            "last_name": "Two",
            "email": "",
            "is_staff": false,
            "is_active": true,
            "date_joined": "2016-10-22T15:21:03Z",
            "groups": [],
            "user_permissions": []
        }
    },
    {
        "model": "myapp.userprofile",
        "pk": 1,
        "fields": {
            "user": 1,
            "money": 100
        }
    },
    {
        "model": "myapp.userprofile",
        "pk": 2,
        "fields": {
            "user": 2,
            "money": 100
        }
    },
    {
        "model": "myapp.userprofile",
        "pk": 3,
        "fields": {
            "user": 3,
            "money": 100
        }
    },
    {
        "model": "myapp.userprofile",
        "pk": 4,
        "fields": {
            "user": 4,
            "money": 100
        }
    }
]

Thanks for any help,

Answer 1

Exclude ContentType and Auth Permissions objects when creating a db dump.

python manage.py dumpdata --natural-foreign --natural-primary -e contenttypes -e auth.Permission --indent 2 > dump.json

After that you should be able to run the command without any issue

python manage.py loaddata dump.json

Credit to https://www.coderedcorp.com/blog/how-to-dump-your-django-database-and-load-it-into-/ for saving my day

Answer 2

Today ( 24th, April, 2020 ) I had a similar problem with Django 2.2

My fixtures file was as simple as this:

[
{
    "model": "contenttypes.contenttype",
    "pk": 1,
    "fields": {
        "app_label": "admin",
        "model": "logentry"
    }
},
{
    "model": "contenttypes.contenttype",
    "pk": 2,
    "fields": {
        "app_label": "auth",
        "model": "permission"
    }
}]

When I ran ./manage.py loaddata initial_data.json , I got:

django.db.utils.IntegrityError: Problem installing fixture '/home/user/reponame/projectname/initial_data.json': Could not load contenttypes.ContentType(pk=2): UNIQUE constraint failed: django_content_type.app_label, django_content_type.model

What I did to make it work was just rename the pk to id for the contenttypes.contenttype model. After that, the migration worked as expected.

./manage.py loaddata initial_data.json 
Installed 2 object(s) from 1 fixture(s)

After the change, my initial_data.json file was:

[
{
    "model": "contenttypes.contenttype",
    "id": 1,
    "fields": {
        "app_label": "admin",
        "model": "logentry"
    }
},
{
    "model": "contenttypes.contenttype",
    "id": 2,
    "fields": {
        "app_label": "auth",
        "model": "permission"
    }
}]

It is worth mentioning that my original initial_dataj.json has many other models, but renaming pk to id only for the contenttypes.contenttype solved my problem.

Answer 3

I had a similar problem. Inspired by this post:

https://github.com/yourlabs/django-cities-light/issues/89 (See 'how to fix it')

before running the loaddata command, I commented the receiver signal decorator before the 'saving function', and it worked.

Answer 4

转到json文件并将evey单个'pk'更改为'id'如果你使用vs代码你可以选择1并按cmd/ctrl + f2作为快捷方式

Answer 5

Had the same problem while exporting and importing a model with a ManyToMany relation. This was, because I manually speficied the ManyToMany through model while exporting, what caused an unique constraint error.

class MyModel(model.Model):
    
    groups = models.ManyToManyField(
        'myapp.mymodel',        
        
    )

You only need to execute dumpdata myapp.mymodel , not `dumpdata myapp.mymodel myapp.mymodel_groups"

Otherwise, your through model data is in the export twice, and causes a unique constraint error.

It`sa good question how this behaves, when you specify an explicit through model...i don't know and have no time to test :)

Answer 6

在加载夹具时注释您的信号。