private function updateSchema($articleNumber)
{
try {
$this->orm->getRepository('Newscoop\\Image\\ArticleImage')->findOneBy(array('articleNumber' => (int) $articleNumber));
} catch (\Exception $e) {
if ($e->getCode() === '42S22') {
$this->orm->getConnection()->exec('ALTER TABLE ArticleImages ADD is_default INT(1) DEFAULT NULL');
}
}
}