Codeigniter: mysql transaction and affected_rows

I need to do multiple insert/update so i came up with transaction to roll back if anything goes wrong. Besides, my application should update the record if already exists, and insert if not.

So first of all i try to update a record using a unique id, if it return affected_rows=0 i continue wih insert.

Probably i miss something within transaction/affected rows, it always return affected_rows=0.

Below is the code:

$this->db->trans_start();

   $this->db->where('order_id', $order_id);
   $this->db->where('order_sta开发者_Python百科tus', 'Active');
   $this->db->update('orders', $order);

   $this->db->where('order_id', $order_id);
   $this->db->where('sku', $item_sku);
   $this->db->update('order_items', $order_items);

$this->db->trans_complete();

if ($this->db->affected_rows()==0){
   $this->db->trans_start();
       $this->db->insert('orders', $order);
       $this->db->insert('order_items', $order_items);
   $this->db->trans_complete();
}

Thanks in advance!

---

I use MySQL's ON DUPLICATE KEY UPDATE to handle that case. However, CodeIgniter's ActiveRecord implementation does not support this natively, and the accepted answer in this thread:

How would I use ON DUPLICATE KEY UPDATE in my CodeIgniter model?

Seems to be dead. So, consider just using raw MySQL instead of the ActiveRecord pattern; this is fairly common amongst CI developers (I do not use their implementation of AR).