File "import.py", line 35, in clear
    eval('models.%s' % n).objects.all().delete()
  File "/usr/lib/python2.5/site-packages/django/db/models/query.py", line 389, in delete
    delete_objects(seen_objs)
  File "/usr/lib/python2.5/site-packages/django/db/models/query.py", line 836, in delete_objects
    update_query.clear_related(field, pk_list)
  File "/usr/lib/python2.5/site-packages/django/db/models/sql/subqueries.py", line 211, in clear_related
    self.execute_sql(None)
  File "/usr/lib/python2.5/site-packages/django/db/models/sql/subqueries.py", line 112, in execute_sql
    super(UpdateQuery, self).execute_sql(result_type)
  File "/usr/lib/python2.5/site-packages/django/db/models/sql/query.py", line 1608, in execute_sql
    cursor.execute(sql, params)
  File "/usr/lib/python2.5/site-packages/django/db/backends/util.py", line 18, in execute
    return self.cursor.execute(sql, params)
psycopg2.ProgrammingError: column "address_id" of relation "tables_student" does not exist
