Django migration: django.db.utils.IntegrityError: (1062, "Duplicate entry '' for key 'slug'")

Question

I am having a very similar problem as in the below question: django.db.utils.IntegrityError: (1062, "Duplicate entry '' for key 'slug'")

I also think that the reply marked as accepted will work for me. The problem is that I can't figure how to implement this solution (I was trying to ask in comments to the answer, but I don't have enough reputation). After reading https://docs.djangoproject.com/en/4.1/ref/migration-operations/, nothing became clearer. I tried to search the Internet for guides on how to edit or copy migrations, but I haven't found anything useful to me, apart from discovering that migrations are/can be also files? Until now, I thought that migration is an action, not a file. I am very new to Django, and the only thing I have ever done with migrations is to just run a basic python manage.py migrate and python manage.py makemigrations commands. Would anyone be able to advise what 'copy migrations.AlterField operation twice,' means? How can I copy a migration? And why does it have .AlterField attached to it? This whole paragraph seems like it might be a solution to my problem, but my knowledge is insufficient to figure out what to do with it... Could someone please explain how to approach this?

score 0 · Answer 1 · answered Apr 03 '23 at 23:51

The problem is that you're getting an error message saying there's a duplicate entry in the slug column of your database table. This means that there are two or more items in your table with the same name, which is not allowed.

To solve this problem, you will need to create a new migrations file that helps Django keep track of changes you want to make to the database. Then, you'll need to write some code in that file that will make sure that every name in the slug column is different.

So for the instructions:

1 - Open you preferred command line, and navigate to the directory of your Django project.

2 - Run the following command, to make an empty migrations file in the app in which the model that you are having a problem with is in: python manage.py makemigrations --empty myapp

3 - Open the new migrations file which is in the myapp/migrations directory.

4 - Add this code to the operations list in in the file:

from django.db import migrations, models

class Migration(migrations.Migration):

    dependencies = [
        ('myapp', '0001_initial'), # replace with the name of your previous migration file
    ]

    operations = [
        migrations.AlterField(
            model_name='mymodel',
            name='slug',
            field=models.SlugField(unique=True),
        ),
        migrations.AlterField(
            model_name='mymodel',
            name='slug',
            field=models.SlugField(unique=True),
        ),
    ]

Also, make sure you replace myapp and mymodel with the names of the app and model you are dealing with. Also, make sure the dependencies list contains the name of your previous migration file.

5 - Save the file.

6 - Go back to your command line, and enter: python manage.py migrate

Once you run the migration, every name will be different in the slug column in your MyModel table. This should take care of the duplicate entry error.

Django migration: django.db.utils.IntegrityError: (1062, "Duplicate entry '' for key 'slug'")

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