What is the best approach to change primary keys in an existing Django app?

Question

I have an application which is in BETA mode. The model of this app has some classes with an explicit primary_key. As a consequence Django use the fields and doesn\'t create

Answer 1

I would like to share my case: The column email was the primary key, but now that's wrong. I need to change the primary key to another column. After trying some suggestions, I finally came up with the most simple solution:

1. First, drop the old primary key. This step requires custom the migrations a bit:

• edit the model to replace primary_key=True on email column by blank=True, null=True
• run makemigrations to create a new migration file and edit it like this:

class Migration(migrations.Migration):

    dependencies = [
        ('api', '0026_auto_20200619_0808'),
    ]
    operations = [
        migrations.RunSQL("ALTER TABLE api_youth DROP CONSTRAINT api_youth_pkey"),
        migrations.AlterField(
            model_name='youth', name='email',
            field=models.CharField(blank=True, max_length=200, null=True))
    ]

• run migrate

2. Now your table has no primary key, you can add a new column or user an old column to be a primary key. Just change the model then migrate. Do some extra script if you need a new column to fill and make sure it includes unique values only.