防止选择多个图像，并在Codeigniter的图像上传功能中仅选择单个图像

我想停止选择多个图像，而只选择单个图像。在此示例中，我在codeigniter中处理图像上载，我可以选择多个图像，但是我只需要选择扔掉的单个图像即可。所以我该如何更改选择以选择单个图像。同样在这个例子中，当我们编辑上传的图像时，旧的图像将被从数据库中删除，我想改变它，但是我不知道在哪里以及如何改变它的代码。

这是我的控制器。

public function index()
{



    $getdata = $this->db->query("SELECT p.id,p.product_description,pd.product_name FROM g_product AS p INNER JOIN g_product_detail AS pd ON p.id = pd.product_id GROUP BY p.id ORDER BY p.id ASC");


    $this->load->view('header');
    $this->load->view('gallery2/index',array('data' => $getdata));



    $this->load->view('footer');


}

public function form()
{
    $this->load->view('gallery2/form', array('error' => ''));
}

public function delete($id)
{
    $getpic = $this->db->query("SELECT full_path FROM g_product_detail WHERE product_id = '{$id}'");
        foreach($getpic->result() as $row)
        {
            unlink($row->full_path);
        }
        $this->db->where('product_id',$id);
        $this->db->delete('g_product_detail');

        $this->db->where('id',$id);
        $this->db->delete('g_product');

        redirect('gallery2/index');
}

private function setup_upload_option()
{
    $config = array();
    $config['upload_path']      = './uploadmulti';
    $config['allowed_types']    = 'jpg|png|gif';
    $config['encrypt_name']     = TRUE;
    $config['overwrite']        = False;
    return $config;
}

public function edit($id)
{
    $getrow = $this->db->query("SELECT * FROM g_product WHERE id= '{$id}' ");
    $row = $getrow->row();


$getdetail = $this->db->query("SELECT * FROM g_product_detail WHERE product_id = '{$id}'");

    $this->load->view('header');
    $this->load->view('gallery2/edit',array('row' => $row,'result' => $getdetail));
    $this->load->view('footer');
}

public function do_update()
{
    $id = $this->input->post('id');
    $data = array(
                    'product_description' => $this->input->post('product_description')


                 );
    $this->db->where('id',$id);
    $te = $this->db->update('g_product',$data);

    if(!empty($_FILES['userfile']['name'][0]))
    {
        $getpic = $this->db->query("SELECT full_path FROM g_product_detail WHERE product_id = '{$id}'");
        foreach($getpic->result() as $row)
        {
            unlink($row->full_path);
        }
        $this->db->where('product_id',$id);
        $this->db->delete('g_product_detail');

        $this->load->library('upload');
    $files = $_FILES;

        $count = count($_FILES['userfile']['name']);
        for($i=0;$i<$count;$i++)
        {
        $_FILES['userfile']['name'] = $files['userfile']['name'][$i];
        $_FILES['userfile']['type'] = $files['userfile']['type'][$i];
        $_FILES['userfile']['tmp_name'] = $files['userfile']['tmp_name'][$i];
        $_FILES['userfile']['size'] = $files['userfile']['size'][$i];
        $_FILES['userfile']['error'] = $files['userfile']['error'][$i];

        $this->upload->initialize($this->setup_upload_option());
        if($this->upload->do_upload() == False)
        {
            $error = array('error' => $this->upload->display_errors());
            $this->load->view('gallery2/form', $error);
        }
        else
        {
            $data = $this->upload->data();
            $dataarray = array(

                'product_id' => $id,
                'product_name' =>$data['file_name'],
                'product_size' =>$data['file_size'],
                'product_ext' =>$data['file_ext'],
                'full_path' =>$data['full_path']
                );
            $this->db->insert('g_product_detail',$dataarray);


        }
    }
    redirect("gallery2/index");
    }
    else
    {
        redirect("gallery2/index");
    }


}


public function do_upload()
{
    $this->load->library('upload');
    $files = $_FILES;

$data = array(
'product_description' => $this->input->post('product_description')
            );
    $ch = $this->db->insert('g_product',$data);
    $id = $this->db->insert_id();
    if($ch > 0)
    {




    $count = count($_FILES['userfile']['name']);
    for($i=0;$i<$count;$i++)
    {
        $_FILES['userfile']['name'] = $files['userfile']['name'][$i];
        $_FILES['userfile']['type'] = $files['userfile']['type'][$i];
        $_FILES['userfile']['tmp_name'] = $files['userfile']['tmp_name'][$i];
        $_FILES['userfile']['size'] = $files['userfile']['size'][$i];
        $_FILES['userfile']['error'] = $files['userfile']['error'][$i];

        $this->upload->initialize($this->setup_upload_option());
        if($this->upload->do_upload() == False)
        {
            $error = array('error' => $this->upload->display_errors());
            $this->load->view('gallery2/form', $error);
        }
        else
        {
            $data = $this->upload->data();
            $dataarray = array(

                'product_id' => $id,
                'product_name' =>$data['file_name'],
                'product_size' =>$data['file_size'],
                'product_ext' =>$data['file_ext'],
                'full_path' =>$data['full_path']
                );
            $this->db->insert('g_product_detail',$dataarray);


        }
    }

    redirect('gallery2/index');
    }

}