merhaba arkadaşlar codeigniterda slider eklemeye çalışıyorum ama eklenmiyor. Modal kullanıyorum. Hata veriyor.

controller dosyam:

<?php
defined('BASEPATH') OR exit('No direct script access allowed');

class Sliders extends CI_Controller {

    /**
     * Index Page for this controller.
     *
     * Maps to the following URL
     *        http://example.com/index.php/welcome
     * - or -
     *        http://example.com/index.php/welcome/index
     * - or -
     * Since this controller is set as the default controller in
     * config/routes.php, it's displayed at http://example.com/
     *
     * So any other public methods not prefixed with an underscore will
     * map to /index.php/welcome/<method_name>
     * @see https://codeigniter.com/user_guide/general/urls.html
     */
    public function __construct()
    {
        parent:: __construct();
        $this->load->model("default_model");
    }

    public function index()
    {
        $viewData  = new stdClass();

        $sliders    = $this->default_model->get_all("sliders",array(),"rank ASC");



        $settings= $this->default_model->get("settings",array("id"=>1));
        $viewData->settings = $settings;


        $viewData->title = $settings->title;
        $viewData->sliders   = $sliders;
        $viewData->url = "sliders";
        $this->load->view('sliders',$viewData);
    }

    public function insert()
    {
        $content        = $this->input->post("content");
        $btn_left       = $this->input->post("btn_left");
        $btn_right      = $this->input->post("btn_right");
        $btn_left_link  = $this->input->post("btn_left_link");
        $btn_right_link = $this->input->post("btn_right_link");

        if(!$content || !$btn_left || !$btn_right || !$btn_left_link || !$btn_right_link ) {
            $alert = array(
                'title' => "Dikkat!",
                'subtitle' => "Lütfen form alanında boş stun bırakmayınız!",
                'type' => "warning"
            );
            $this->session->set_flashdata("alert", $alert);
            redirect(base_url("sliders"));
        }else{
            if(!empty($_FILES["image"]["name"]))
            {

                $config["upload_path"]   = "../uploads/sliders/";
                $config["allowed_types"] = "gif|jpg|jpeg|png|svg";
                $config["file_name"]     = uniqid();

                $this->load->library("upload",$config);
                $upload = $this->upload->do_upload("image");

                if($upload)
                {
                    $uploaded_filename = $this->upload->data("file_name");

                    $config["image_library"]   = "gd2";
                    $config["source_image"]    =  "../uploads/sliders/".$uploaded_filename;
                    $config["create_thumb"]    = FALSE;
                    $config["maintain_ratio"]  = TRUE;
                    $config["quality"]         ="100%";
                    $config["witdh"]  = 1100;
                    $config["height"] = 500;

                    $this->load->library("image_lib",$config);
                    $this->image_lib->resize();

                    $insert = $this->default_model->insert("sliders",
                        array("image"=>"sliders/".$uploaded_filename,
                            "content"=>$content,
                            "btn_left"=>$btn_left,
                            "btn_right"=>$btn_right,
                            "btn_left_link"=>$btn_left_link,
                            "btn_right_link"=>$btn_right_link,
                            "status"=> 1,
                            "rank"=> 0,
                            "created_at"=>date("Y-m-d")));

                    if($insert)
                    {
                        $alert = array(
                            'title'    => "Tebrikler!",
                            'subtitle' => "İşlem başarılı bir şekilde gerçekleşti!",
                            'type'     => "success"
                        );

                    }else{
                        $alert = array(
                            'title'    => "Hata!",
                            'subtitle' => "İşlem başarısız oldu.Tekrar deneyin!",
                            'type'     => "error"
                        );
                    }
                    $this->session->set_flashdata("alert",$alert);
                    redirect(base_url("sliders"));

                }else{

                    $alert = array(
                        'title'    => "Hata!",
                        'subtitle' => "Slider yüklenirken işlem başarısız oldu.Tekrar deneyin!",
                        'type'     => "error"
                    );

                    $this->session->set_flashdata("alert",$alert);
                    redirect(base_url("sliders"));

                }


            }else{

                $alert = array(
                    'title'    => "Hata!",
                    'subtitle' => "Slider resim alanı boş olamaz.Tekrar deneyin!",
                    'type'     => "error"
                );

                $this->session->set_flashdata("alert",$alert);
                redirect(base_url("sliders"));

            }
        }
    }

    public function update($id)
    {
        $content        = $this->input->post("content");
        $btn_left       = $this->input->post("btn_left");
        $btn_right      = $this->input->post("btn_right");
        $btn_left_link  = $this->input->post("btn_left_link");
        $btn_right_link = $this->input->post("btn_right_link");

        if(!$content || !$btn_left || !$btn_right || !$btn_left_link || !$btn_right_link ) {
            $alert = array(
                'title' => "Dikkat!",
                'subtitle' => "Lütfen form alanında boş stun bırakmayınız!",
                'type' => "warning"
            );
            $this->session->set_flashdata("alert", $alert);
            redirect(base_url("sliders"));
        }else{
            if(!empty($_FILES["image"]["name"]))
            {
                $image_data = $this->default_model->get("sliders",array("id"=>$id));

                unlink("uploads/".$image_data->image);

                $config["upload_path"]   = "../uploads/sliders/";
                $config["allowed_types"] = "gift|jpg|jpeg|png|svg";
                $config["file_name"]     = uniqid();

                $this->load->library("upload",$config);
                $upload = $this->upload->do_upload("image");

                if($upload)
                {
                    $uploaded_filename = $this->upload->data("file_name");

                    $config["image_library"]   = "gd2";
                    $config["source_image"]    =  "../uploads/sliders/".$uploaded_filename;
                    $config["create_thumb"]    = FALSE;
                    $config["maintain_ratio"]  = TRUE;
                    $config["quality"]         ="100%";
                    $config["witdh"]  = 1100;
                    $config["height"] = 500;

                    $this->load->library("image_lib",$config);
                    $this->image_lib->resize();

                    $update = $this->default_model->update("sliders",
                        array("id"=>$id),
                        array("image"=>"sliders/".$uploaded_filename,
                            "content"=>$content,
                            "btn_left"=>$btn_left,
                            "btn_right"=>$btn_right,
                            "btn_left_link"=>$btn_left_link,
                            "btn_right_link"=>$btn_right_link));

                    if($update)
                    {
                        $alert = array(
                            'title'    => "Tebrikler!",
                            'subtitle' => "İşlem başarılı bir şekilde gerçekleşti!",
                            'type'     => "success"
                        );

                    }else{
                        $alert = array(
                            'title'    => "Hata!",
                            'subtitle' => "İşlem başarısız oldu.Tekrar deneyin!",
                            'type'     => "error"
                        );
                    }
                    $this->session->set_flashdata("alert",$alert);
                    redirect(base_url("sliders"));

                }else{

                    $alert = array(
                        'title'    => "Hata!",
                        'subtitle' => "Slider yüklenirken işlem başarısız oldu.Tekrar deneyin!",
                        'type'     => "error"
                    );

                    $this->session->set_flashdata("alert",$alert);
                    redirect(base_url("sliders"));

                }


            }else{

                // resim güncellenmese gelicek...olan form
                $update = $this->default_model->update("sliders",
                    array("id"=>$id),

                    array( "content"=>$content,
                        "btn_left"=>$btn_left,
                        "btn_right"=>$btn_right,
                        "btn_left_link"=>$btn_left_link,
                        "btn_right_link"=>$btn_right_link));

                if($update)
                {
                    $alert = array(
                        'title'    => "Tebrikler!",
                        'subtitle' => "İşlem başarılı bir şekilde gerçekleşti!",
                        'type'     => "success"
                    );

                }else{
                    $alert = array(
                        'title'    => "Hata!",
                        'subtitle' => "İşlem başarısız oldu.Tekrar deneyin!",
                        'type'     => "error"
                    );
                }
                $this->session->set_flashdata("alert",$alert);
                redirect(base_url("sliders"));


            }
        }
    }


    public function delete($id)
    {
        $image_data = $this->default_model->get("sliders",array("id"=>$id));

        unlink("uploads/".$image_data->image);

        $delete = $this->default_model->delete("sliders",array("id"=>$id));
        if($delete)
        {
            $alert = array(
                'title'    => "Tebrikler!",
                'subtitle' => "Silme işlemi başarışı bir şekilde gerçekleşti!",
                'type'     => "success"
            );

        }else{
            $alert = array(
                'title'    => "Hata!",
                'subtitle' => "İşlem başarısız oldu.Tekrar deneyin!",
                'type'     => "error"
            );
        }
        $this->session->set_flashdata("alert",$alert);
        redirect(base_url("sliders"));
    }

    public function isactivesetter($id)
    {
        if($id)
        {
            $isActive = ($this->input->post("data") == "true") ? 1 : 0;
            $this->default_model->update("sliders",array("id"=>$id),array("status"=>$isActive));
        }
    }

    public function ranksetter()
    {
        $data = $this->input->post("data");
        parse_str($data,$rank);
        $value = $rank["rank"];
        foreach ($value as $rank =>$id)
        {
            $this->default_model->update("sliders",array("id"=>$id),array("rank"=>$rank));
        }
    }




}

database tablo ismi sliders