CodeIgniter将多维数组作为单独的行插入到数据库表中

saving post value to an array.

$data2 = array(
  'invoice_id' =>($id),
  'order_id' => $this->input->post('order_id'),
  'invoiceitems_servicetype' =>$this->input->post('type'),
  'invoiceitems_quantity' => $this->input->post('quantity'),
  'invoiceitems_unitprice' => $this->input->post('rate'),
  'invoiceitems_notes' => $this->input->post('description')
      );

 $this->db->insert('abc_invoiceitems', $data2);

print_r($data2);

Array Structure.

Array
(
    [invoice_id] => 21
    [order_id] => 1
    [invoiceitems_servicetype] => Array
        (
            [0] => Order
            [1] => Miscellaneous
            [2] => Order
        )

    [invoiceitems_quantity] => Array
        (
            [0] => 5
            [1] => 64
            [2] => 88
        )

    [invoiceitems_unitprice] => Array
        (
            [0] =>  5
            [1] =>  6
            [2] =>  8
        )

    [invoiceitems_notes] => Array
        (
            [0] => test Data1
            [1] => test Data2
            [2] => test Data3
        )

)

Insert array values to database table.

TABLE NAME --- abc_invoiceitems 
 +------------+----------+--------------------------+-----------------------+------------------------+--------------------+
 | invoice_id | order_id | invoiceitems_servicetype | invoiceitems_quantity | invoiceitems_unitprice | invoiceitems_notes |
 +------------+----------+--------------------------+-----------------------+------------------------+--------------------+

I got this following error and the error is :

the values are returning as array.

INSERT INTO abc_invoiceitems (invoice_id, order_id, invoiceitems_servicetype, invoiceitems_quantity, invoiceitems_unitprice, invoiceitems_notes) VALUES ('21', '1', Array, Array, Array, Array)