I edited the my model field:
From:
principal_contact_info_designation = models.IntegerField()
To:
principal_contact_info_designation = models.CharField(max_length=50)
and I make a migration then I run it, and it shows this:
django.db.utils.OperationalError: cannot ALTER TABLE "principal_contact_info" because it has pending trigger events
I am using python 3.5 and django 1.9.1