如何使用Doctrine2和Symfony2查看自动生成的SQL架构更新SQL查询？

doctrine:
    dbal:
        driver:   %database_driver%
        host:     %database_host%
        port:     %database_port%
        dbname:   %database_name%
        user:     %database_user%
        password: %database_password%
        charset:  UTF8
        options:
            %database_options%

<?php
namespace App\Entity;

use Doctrine\ORM\Mapping as ORM;

/**
 * @ORM\Entity
 */
class MyEntity
{
    /**
     * @ORM\Id
     * @ORM\GeneratedValue
     * @ORM\Column(type="integer")
     */
    private $id;

    /**
     * @ORM\Column(type="string", length=100)
     */
    private $name;

    /**
     * @ORM\Column(type="string", length=100)
     */
    private $email;

    /**
     * @ORM\Column(type="datetime")
     */
    private $createdAt;

    /**
     * @ORM\Column(type="datetime", nullable=true)
     */
    private $updatedAt;
}

<?php
$qb = $entityManager->createQueryBuilder()
    ->select('u')
    ->from('App\Entity\User', 'u');

$query = $qb->getQuery();

$results = $query->getResult();