[Django] Model primary key

models.py:

1. If you didn’t set your own primary key, then Django would set the id column same as below.

class TestModel(models.Model):
  id = models.AutoField(auto_created=True, primary_key=True)

2. We can set our primary key column if we need.

class TestModel(models.Model):
  user_id = models.AutoField(auto_created=True, primary_key=True)