Po odoslani formulara ERROR – Column operator does not accept null argument

Zdravim, mam jednoduchy formular na update hodnot v DB, problem je ze ked sa tento formular odosle, tak to dava chybu Column operator does not accept null argument na riadku ->where('dateDec = ? AND startTime = ?', $this->dayDec, $this->startTime). Nedava mi tento problem zmysel, kedze aj v pripade realodu stranky by mali byt hodnoti pristupne, preto by som bol rad o trochu podrobenjsie vysvetlenie.

public function renderEdit($dayDec, $startTime) {
	$this->dayDec = $dayDec;
	$this->startTime = $startTime;
}

public function createComponentOrderEdit() {
    $form = new form;

    $orderDetails = $this->database->table('orders')
        ->where('dateDec = ? AND startTime = ?', $this->dayDec, $this->startTime)
        ->fetch();

    $this->orderId = $orderDetails->id;

    $form->addText('name')
        ->setDefaultValue($orderDetails->name);
    $form->addText('tel')
        ->setHtmlType('number')
        ->setDefaultValue($orderDetails->tel);
    $form->addEmail('email')
        ->setDefaultValue($orderDetails->email);
    $form->addText('price')
        ->setHtmlType('number')
        ->setDefaultValue($orderDetails->price);
    $form->addText('deposit')
        ->setHtmlType('number')
        ->setDefaultValue($orderDetails->deposit);
    $form->addText('comment')
        ->setDefaultValue($orderDetails->comment);
    $form->addSubmit('submit');
    $form->onSuccess[] = [$this, 'orderEditSucceeded'];
    return $form;
}

public function orderEditSucceeded($form)
{
    $values = $form->getValues();

    $this->database->table('orders')->where('id', $this->orderId)->update([
        'price' => $values['price'],
        'deposit' => $values['deposit'],
        'name' => $values['name'],
        'tel' => $values['tel'],
        'email' => $values['email'],
        'comment' => $values['comment'],
    ]);

    $this->redirect('Calendar:');
}

Editoval kerafura (22. 2. 2018 12:59)