django - NOT NULL constraint failed when running `migrate` -

i changed models.py file , when running migrate error. property onetoonefield(). have tried adding null=true doesn't seem fix it. weird when comment out property , run makemigrations followed migrate, still exact same error. there way fix this? model looks this:

class estimator(employee):     avg_estimate = models.integerfield()   class job(models.model):     created = models.datetimefield(auto_now_add=true)     estimator = models.onetoonefield(estimator, null=true)     address = models.charfield(max_length=100)     completed = models.booleanfield(default=false) 

my guess have created migration without null=true, won't migrate, created second migration null=true.

running "migrate" run both migrations in order, first 1 fail again.

assuming case, 1: delete 2 recent files in migrations folder. (open them first confirm creating migrations described before deleting them). 2: run makemigrations again, null=true in models.py

this should create equivalent of second migration file, without failing intermediate migration.