在codeigniter中添加两个数组变量

Question

I am building a system where i need to update the value in the database field but before doing that i need to take the current value in the database then adding it to the current value the following is a code from the controller.

public function transfer_amount(){



    $email  =  $this->input->post('view');

    $this->load->model('user_model');

    $data['user_balance'] = $this->user_model->fetch_balance($email);

    $data['balance'] = $this->input->post('amount');

    $data['total'] = $this->math->add($data['balance'],$data['user_balance']);


    $data = array(

            'balance' => $data['total'],

    );




    if($this->user_model->transfer_amount($data,$email)== true){


        $this->load->view('layer_service/success',$data);


    }
    else
    {


        $this->load->view('layer_service/unsuccessfull',$data);
    }



}

}

then the code in the module that fetch the current balance from the database is as following.

 function fetch_balance($email){


    $this->db->select('balance');
    $this->db->from('tbl_users');
    $this->db->where('email', $email);

    $query = $this->db->get();
    $result = $query->result();

    return $result;


}