Entity::addBinding

private function addBinding($entityId, $entityType)
{
	$res = BindingTable::add([
		'BINDING_TYPE' => static::$bindingType,
		'BINDING_ID' => $this->bindingId,
		'ENTITY_TYPE' => $entityType,
		'ENTITY_ID' => $entityId
	]);
	if ($res->isSuccess())
	{
		return $res->getId();
	}
	else
	{
		return null;
	}
}