foreignkey (user) in models

Question

I read the docs and this post... Django - Foreign Key to User model

I followed what it said and I still cannot get it to work. When I try to run the migrations I get this error in the traceback...

django.db.utils.ProgrammingError: column "author_id" cannot be cast automatically to type integer
HINT:  You might need to specify "USING author_id::integer".

I just don't know how to go about fixing that error.

from django.db import models
from django.contrib.auth.models import User

# Create your models here.
class BlogCategory(models.Model):
    '''model for categories'''

    title = models.CharField(max_length=30)
    description = models.CharField(max_length=100)


class BlogPost(models.Model):
    '''a model for a blog post'''

    author = models.ForeignKey(User)
    date = models.DateField()
    title = models.CharField(max_length=100)
    post = models.TextField()

Are you using the default user model? Please include the relevant migration file — Sayse, Dec 16 '15 at 07:38

score 168 · Answer 1 · edited Jun 14 '19 at 09:15

168

Don't use the User model directly.

From the documentation

Instead of referring to User directly, you should reference the user model using django.contrib.auth.get_user_model()

When you define a foreign key or many-to-many relations to the user model, you should specify the custom model using the AUTH_USER_MODEL setting.

Example:

from django.conf import settings
from django.db import models

class Article(models.Model):
    author = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.CASCADE,
    )

edited Jun 14 '19 at 09:15

Flimm

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answered Dec 04 '16 at 01:22

Andrew E

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4

One thing that confused me when using this answer was whether or not I needed to define the `AUTH_USER_MODEL` setting in `settings.py`. Documentation says that is not necessary - `This method will return the currently active user model – the custom user model if one is specified, or User otherwise.` – Jordan Carroll Sep 09 '17 at 14:21
8

The [documentation](https://docs.djangoproject.com/en/1.10/topics/auth/customizing/#auth-custom-user) states: "Django allows you to override the default user model by providing a value for the AUTH_USER_MODEL setting". Basically: *if* you are providing a custom `User` model you *must* provide the `AUTH_USER_MODEL` setting. – Andrew E Sep 10 '17 at 04:09

score 3 · Answer 2 · edited Aug 16 '17 at 17:59

3

If you created a custom User model, you would use setting.AUTH_USER_MODEL, if not you can go ahead an use User model

Referencing Django User model

edited Aug 16 '17 at 17:59

Martin Evans

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answered Aug 16 '17 at 17:18

Jermaine

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what if presently not using custom model and in future there are chances to use which option will be better then? – Krishnadas PC Apr 25 '23 at 07:18
1

Always go with using a custom user model from the initial setup, because it will be difficult making the changes later on. – Jermaine Apr 25 '23 at 20:34

score 0 · Answer 3 · edited May 23 '17 at 10:31

0

the column "author_id" doesn't exist, looks like is the same problem from here : Django suffix ForeignKey field with _id , so to avoid this traceback you may use :

author = models.ForeignKey(User, db_column="user")

edited May 23 '17 at 10:31

Community

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answered Apr 18 '17 at 17:58

Sérgio

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score -15 · Accepted Answer · answered Dec 16 '15 at 07:27

-15

I do not know the "settings.AUTH_USER_MODEL" approach but a well-known approach and commonly used is the "Auth.User" model. Something like this on your end.

from django.contrib.auth.models import User

class BlogPost(models.Model):
    '''a model for a blog post'''

    author = models.ForeignKey(User)
    date = models.DateField()
    title = models.CharField(max_length=100)
    post = models.TextField()

answered Dec 16 '15 at 07:27

Dean Christian Armada

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I tried that before looking it up and doing the other way. I get the same error – Joff Dec 16 '15 at 07:29
Providing you haven't overridden the [`AUTH_USER_MODEL` setting](https://docs.djangoproject.com/en/1.9/ref/settings/#auth-user-model), the model you're referring to *is* the default – Sayse Dec 16 '15 at 07:37
1

https://docs.djangoproject.com/en/1.9/topics/auth/customizing/#substituting-a-custom-user-model, as what the link says the "AUTH_USER_MODEL" should be the user model of a certain app, have you done that on your end? Or you might want to provide other extra details like the value of your AUTH_USER_MODEL – Dean Christian Armada Dec 16 '15 at 07:41
I have not defined a user model for that class. Is there not some way to make it a foreign key to all users in my database? – Joff Dec 16 '15 at 07:52
from django.contrib.auth.models import User author = models.ForeignKey(User) is the best answer I got for you in your case as it is what I have always used – Dean Christian Armada Dec 16 '15 at 08:09
@DeanChristianArmada I get the same error when I use that way – Joff Dec 16 '15 at 08:30
I just tried it and emptied out the database of the previous post entries – Joff Dec 16 '15 at 08:31
I don't understand what happened here. The code in this answer looks like a snippet from the one in the question. – 101is5 Feb 01 '22 at 18:25

foreignkey (user) in models

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