Django AUTO INCREMENT for PK

December 6, 2022

I have some models in my Django app and I saw the field ‘auto_increment_id’ (as PK) doesn’t work as ‘AUTO INCREMENT’ (the DB is Postgres).

I made 2 records with auto_increment_id 1 and 2, delete record 2 and make a new one with auto_increment_id=3 instead of auto_increment_id=2.

models.py

class Testme(models.Model):
    auto_increment_id = models.AutoField(primary_key=True)
    year = models.ForeignKey(
        Year,
        verbose_name="Year",
        blank=False,
        on_delete=models.CASCADE,
    )

    def __str__(self):
        return str(self.auto_increment_id)

How can I fix it?

Thanks a lot!

>Solution :

There’s nothing to fix. Postgres uses a counter for this – it doesn’t take "the first free space" in the id range, it just uses the next value of the counter.

It’s only there to be a unique value, so having gaps in the range where you’ve deleted records is not an issue.

(Also, no need to add this yourself – if you don’t specify primary_key=True on any field, Django will automatically add an id field that does this).