I have form in my CodeIgniter View, where checkboxes are generated from database.
When I submit form without checking any checkbox, I get error:
Message: Undefined index: formChecks
My Controller:
public function formularz2()
{
    $this->load->helper(array('form', 'url'));
    $this->load->library('form_validation');
    //Names of checkboxes generated from model (DB)
    $data['szkolenia'] = $this->Szkolenie_m->pobierz();
    //Validation
    $this->form_validation->set_rules('imie', 'Imię', 'required');
    $this->form_validation->set_rules('accept_terms_checkbox', 'Checkbox', 'required');
    $this->form_validation->set_message('required', 'Błąd: Powyższe pole jest wymagane');
    //SUBMMIT
    if (!empty($_POST))
    {
    $konsultant = $this->uri->segment(3);
    $dane = array(
        'email1' => $this->input->post('email'),
        'imie' => $this->input->post('imie'),
        'nazwisko' => $this->input->post('nazwisko'),
        'nazwa_firmy' => $this->input->post('firma'),
        'konsultant_id' => $konsultant,
    );
    //Adding checked boxes to another database
    $boxes = $_POST['formChecks'];
    $N = count($boxes);
    $ostatni_id = $this->Osoby_m->ostatni_id();
    for($i=0; $i < $N; $i++)
    {
            $this->Osoby_m->nowy_wpis_formularz($boxes[$i]);    
    }       
    $this->Osoby_m->nowa_osoba($dane);  
    }   
    if ($this->form_validation->run() == FALSE)
    {
        $this->load->view('formularz', $data);
    }
    else
    {
        $this->load->view('wyslano_formularz');
    }
}
My View:
                <?php echo form_open(); ?>
              <div class="form-group">
                <label for="email" class="col-sm-2 control-label">Email:</label>
                <div class="col-sm-10" style="color: #c92e39;">
                  <input type="email" class="form-control" id="email" name="email" placeholder="Email" value="<?php echo set_value('email'); ?>">
                  <p class="help-block"><?php echo form_error('email'); ?></p>
                </div>
              </div>
              <div class="form-group">
                <label for="imie" class="col-sm-2 control-label">Imię:</label>
                <div class="col-sm-10" style="color: #c92e39;">
                  <input type="text" class="form-control" id="imie" name="imie" placeholder="Imię" value="<?php echo set_value('imie'); ?>">
                  <p class="help-block"><?php echo form_error('imie'); ?></p>
                </div>
              </div>
              <div class="form-group">
                <label for="nazwisko" class="col-sm-2 control-label">Nazwisko:</label>
                <div class="col-sm-10" style="color: #c92e39;">
                  <input type="text" class="form-control" id="nazwisko" name="nazwisko" placeholder="Nazwisko" value="<?php echo set_value('nazwisko'); ?>">
                  <p class="help-block"><?php echo form_error('nazwisko'); ?></p>
                </div>
              </div>
              <div class="form-group">
                <label for="firma" class="col-sm-2 control-label">Firma:</label>
                <div class="col-sm-10" style="color: #c92e39;">
                  <input type="text" class="form-control" id="firma" name="firma" placeholder="Firma" value="<?php echo set_value('firma'); ?>">
                  <p class="help-block" style="color:red;"><?php echo form_error('firma'); ?></p>
                </div>
              </div>
            <div class="col-sm-12" style="margin-bottom: 30px; margin-top: 30px;"><h3>Wybierz interesujące Cię szkolenia</h3></div>
              <div class="form-group">
                <label class="col-sm-2 control-label">Szkolenia:</label>
                <div class="col-sm-10">
    ////////////////////////
    ///MY CHECKBOXES LOOP///
    ////////////////////////
                  <?php foreach ($szkolenia as $szkolenie): ?>
                  <div class="checkbox">
                        <label><input id="szkolenie<?php echo $szkolenie->id; ?>" type="checkbox" name="formChecks[]" value="<?php echo $szkolenie->id; ?>"> <?php echo $szkolenie->nazwa_szkolenia; ?></label>         
                        <br>
                    </div>
                    <?php endforeach; ?>
                </div>
              </div>
              <div class="form-group">
                <div class="col-sm-12" style="margin-top: 50px; ">
             <input type="checkbox" name="accept_terms_checkbox" value="1"/> Zgadzam się na otrzymywanie maili od firmy Gamma<br>
              <span style="color: #c92e39;"><p><?php echo form_error('accept_terms_checkbox') ?></p></span>
                </div>
              </div>
              <button type="submit" class="btn btn-lg btn-success" style="margin-top: 50px;">Odbierz Voucher</button>
            <?php echo form_close(); ?>
How I canfix this error, or make validation for checkboxes from database formCheck[]?
 
     
    