zf2 with doctrine2 - how can I find out what's wrong? - debugging

Question

I try to learn Doctrine2 now so I created a trivial Entity (actually I got it from tutorial):
<?php
namespace Application\Entity;
use Doctrine\ORM\Mapping as ORM;
/**
* #ORM\Entity
*/
class Product {
/**
* #ORM\Id
* #ORM\GeneratedValue(strategy="AUTO")
* #ORM\Column(type="integer")
*/
protected $id;
/**
* #ORM\Column(type="string")
*/
protected $name;
public function getId() {
return $this->id;
}
public function getName() {
return $this->name;
}
public function setName($name) {
$this->name;
return $this;
}
}
I also created an action to create and persist such product:
public function createProductAction() {
$em = $this->getServiceLocator()->get('Doctrine\ORM\EntityManager');
$em->getConnection()
->getConfiguration()
->setSQLLogger(new \Doctrine\DBAL\Logging\EchoSQLLogger());
$product = new Product();
$product->setName("Test product");
$em->persist($product);
$em->flush();
echo "Created product with ID ".$product->getId();
}
Of course before test I've ran a command to create db scheme (and checked that it's actually created). Simillar code for User runs smoothly but this action reports following:
"START TRANSACTION" INSERT INTO Product (name) VALUES (?)
array (size=1)
1 => null
array (size=1)
1 => string 'string' (length=6)
"ROLLBACK"
What's wrong?? Is there anyway to debug it somehow?? :|