Not null constraint failed. Django Models-Postgres Same error null=True as null=False

Question

I'm having difficulty updating these three models which are linked with Foreign keys Reason they are linked with foreign keys is Events can have multiple Markets and Markets can have multiple Runners.

I'm at my wits end with this not null error. Even If I have a field that causes the issue and I remove the field from my model. Make migrations, migrate and remove the save from my task I still get the exact same error. What is the purpose of this not null argument? Even If I have null=True or null=False on brand new models I still get the error. Not null constraint failed

django.db.utils.IntegrityError: NOT NULL constraint failed: testapp_ma.event_id

I've no idea why this is failing.

Do I need to make sure all fields have a null argument? According to django documentation default is false. For each object my task runs all fields have data. So default of false should be fine. Could this be due to the manner I'm updating the models with my task?

full stacktrace here https://gist.github.com/Cally99/08fed46ba8039fa65d00f53e8a31b37a

class Event(models.Model):
    sport_name = models.CharField(max_length=15)
    event_id = models.BigIntegerField(unique=True, null=False)
    event_name = models.CharField(max_length=200)
    start_time = models.DateTimeField()
    status = models.CharField(max_length=13)

class Market(models.Model):
    event = models.ForeignKey(Event, on_delete=models.CASCADE)
    market_id = models.BigIntegerField(unique=True)
    market_name = models.CharField(max_length=35)
    status = models.CharField(max_length=10)
    volume = models.FloatField(null=True)

class Runner(models.Model):
    market = models.ForeignKey(Market, null=True, default=None, on_delete=models.SET_NULL)
    runner_id = models.BigIntegerField(unique=True)
    event_id = models.BigIntegerField(null=True, default=0)
    name = models.CharField(max_length=100)

tasks.py

@shared_task(bind=True)
def get_events(self):

    api = get_client()
    events = api.market_data.get_events(sport_ids=[9],states=MarketStates.All,
                                                        per_page=200, offset=0,
                                                        include_event_participants=Boolean.T,
                                                        category_ids=None, price_depth=3,
                                                        side=Side.All, session=None)

    for event in events:
        event_name = event["name"]
        event_id = event['id']
        start_time = event['start']
        status = event["status"]

        ev, created = Ev.objects.update_or_create(event_id=event_id)

        ev.event_name = event_name
        ev.start_time = start_time
        ev.status = status
        ev.save()

        markets = event["markets"]
        for market in markets:
            event_id = market['event-id']
            market_id = market['id']
            market_name = market['name']
            status = market['status']
            volume = market['volume']

            ma, created = Ma.objects.update_or_create(market_id=market_id)
            ma.market_name = market_name
            ma.status = status
            ma.volume = volume
            ma.save()

            runners = market["runners"]
            for runner in runners:
                name = runner['name']
                runner_id = runner['id']
                event_id = runner['event-id']

                runner, created = Ru.objects.update_or_create(runner_id=runner_id)
                runner.event_id = event_id
                runner.name = name
                runner.save() 

Answer 1

With the line

Ma.objects.update_or_create(market_id=market_id)

you haven't set the Event for your market object. And given how

event = models.ForeignKey(Event, on_delete=models.CASCADE)

doesn't have null=True , it won't accept any null values.