def _get_pk(self):
    if (not self.pk_fields):
        pk_rows = self.conn.get_primary_keys(self.table_obj)
        self.pk_fields = [r.column_name for r in pk_rows]
    return self.pk_fields
def _get_pk(self):
    if (not self.pk_fields):
        pk_rows = self.conn.get_primary_keys(self.table_obj)
        self.pk_fields = [r.column_name for r in pk_rows]
    return self.pk_fields