Integrityerror: Null Value In Column "city_id " Violates Not-null Constraint

I two model: class City(models.Model): name = models.CharField(max_length=50) country = models.OneToOneField(Country) def __unicode__(self): return self.name

Solution 1:

city = models.OneToOneField(City)

Are you sure you want only one user per city? I think you need

city = models.ForeignKey(City, null=True, blank=True)

null, blank because the sycndb will create a profile and will fail if no city is passed.

Alternatively, you can pass default=default_city_id to the cityForeignKey