python - Django syncdb : "columname" cannot be cast to type integer -

i want deploy django app, when developing used sqlite database. in production, want use postgresql database.

i setup project, copied models, want sync db, when use following command:

python manage.py syncdb 

i following error:

file "/home/oras/webapps/leden_landing/lib/python3.4/django-1.8.2-py3.4.egg/django/db/backends/utils.py", line 64, in execute return  self.cursor.execute(sql, params) django.db.utils.programmingerror: column "studierichting_id" cannot cast type integer 

i don't understand how can happen, know can solve problem?

these models:

class lid(models.model):     voornaam = models.charfield(max_length=30, blank=false)     achternaam = models.charfield(max_length=30, blank=false)     studienummer = models.integerfield()     studierichting = models.foreignkey(studie)  class studie(models.model):     naam = models.charfield(max_length=30) 

since don't have data yet, , database still needs setup, don't understand how can casting error...

finally found it, visgean suggested, still had migrations. after deleted folder, syncdb'ing start :)