insert or update on table "django_admin_log" violates foreign key constraint

Question

Trying to save a post on a django project I got this error

The above exception (insert or update on table "django_admin_log" violates foreign key constraint "django_admin_log_user_id_c564eba6_fk_auth_user_id" DETAIL: Key (user_id)=(1) is not present in table "auth_user". ) was the direct cause of the following exception:

The model:

from django.conf import settings


class Tag(models.Model):
    name = models.CharField(max_length=50)

    def __str__(self):
        return self.name


class Post(models.Model):
    title = models.CharField(max_length=200, db_index=True)
    slug = models.SlugField(max_length=200, db_index=True)
    author = models.ForeignKey(
        settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
    content = models.TextField()
    image = models.ImageField(upload_to='', blank=True, null=True)
    tags = models.ManyToManyField(Tag, blank=True)
    created_on = models.DateTimeField(auto_now_add=True)
    updated_on = models.DateTimeField(auto_now=True)

    class Meta:
        ordering = ['-created_on']

    def __str__(self):
        return self.title

The view:

from django.views.generic import ListView, DetailView
from django.shortcuts import get_object_or_404

from .models import Post


class BlogView(ListView):
    template_name = 'base/blog.html'
    queryset = Post.objects.all()
    paginate_by = 2


class PostView(DetailView):
    model = Post
    template_name = 'base/post.html'

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        pk = self.kwargs['pk']
        slug = self.kwargs['slug']

        post = get_object_or_404(Post, pk=pk, slug=slug)
        context['post'] = post
        return context

How can I solve this problem?

Answer 1

That because the django_admin_log table still contains a foreign key relation to the old auth_user table.

You need to drop this and recreate the table.

psql => DROP table django_admin_log;

For Django >= 1.7

./manage.py sqlmigrate admin 0001 | ./manage.py dbshell

And that's it :)