Notifikasi untuk validasi input/update data di codeigniter

Selamat sore kakak kakak sekalian, saya mau bertanya soal notifikasi untuk validasi data. bagaimana caranya saat saya input/update data nantinya akan ada notifikasi apabila data sudah digunakan. adapun script saya saat ini :

Controller :

//Tambah data Dosen
    public function dosen_tambah()
    {
        $admins = $this->dosen_model;
        $validation = $this->form_validation;
        $validation->set_rules($admins->rules());
        if ($validation->run() == TRUE)
        {
            $admins->simpan();
            $this->session->set_flashdata('success', 'Data Berhasil disimpan');
            if (!$admins)
            {
                header('Location: dosen_data');
            }
            else
            {
                echo "Data Gagal Diupdate";
                echo "<br>";
                echo "<a href='".base_url('admin/dosen_data/')."'>Kembali</a>";
                $this->session->set_flashdata('danger', 'Data Gagal disimpan');
            }
        }
            $this->load->view("admin/data_dosen/dosen_tambah");
    }

Model :

//simpan data tabel dari database
    public function simpan()
    {
        $post = $this->input->post();
        $this->nidn   = $post["nidn"];
        $this->nama_dosen   = $post["nama_dosen"];
        $this->password     = sha1($post["password"]);
        $this->telepon      = $post["telepon"];
        $this->email        = $post["email"];
        $this->alamat       = $post["alamat"];
        $this->db->insert($this->_table, $this);

        if($this->db->affected_rows() > 0){
            return true;
        }
        else
        {
            return false;
        }
    }

//ambil id data dari database
    public function ambil($id)
    {
        return $this->db->get_where($this->_table, ["nidn" => $id])->row();
    }

View :

            <form role="form" action="<?php echo base_url().'admin/dosen_tambah'; ?>" method="POST">
              <div class="box-body">
                <div class="form-group">
                  <label>NIDN</label>
                  <input type="number" name="nidn" id="nidn" class="form-control" required>
                  <?php echo form_error('nidn'); ?>
                </div>
                <div class="form-group">
                  <label>Nama Lengkap</label>
                  <input type="text" name="nama_dosen" id="nama_dosen" class="form-control" required>
                  <?php echo form_error('nama_dosen'); ?>
                </div>
                <div class="form-group">
                  <label>Password</label>
                  <input type="password" name="password" id="password" class="form-control" required>
                  <?php echo form_error('password'); ?>
                </div>
                <div class="form-group">
                  <label>Telepon</label>
                  <input type="number" name="telepon" id="telepon" class="form-control" required>
                  <?php echo form_error('number'); ?>
                </div>
                <div class="form-group">
                  <label>Email</label>
                  <input type="email" name="email" id="email" class="form-control" required>
                  <?php echo form_error('email'); ?>
                </div>
                <div class="form-group">
                  <label>Alamat</label>
                  <textarea type="text" name="alamat" id="alamat" class="form-control" required></textarea>
                  <?php echo form_error('alamat'); ?>
                </div>
              </div>
              <div class="box-footer">
                <button type="submit" value="simpan" class="btn btn-primary">Submit</button>
              </div>
            </form>

Notifikasi saat ini :