Symfony2 setting other rows to 0 after/before flush - symfony

Question

Here's what I'm having trouble with.
I've a Table which contains a column called shown_on_homepage and only one row should be set to 1, the rest should all be set to 0. I'm trying to add a new row to the database and this one should be set to 1, setting the one that previously had a 1 to 0.
In MySQL I know this can be achieved by issuing an update before the insert:
UPDATE table_name SET shown_on_homepage = 0
Here's my Entity:
class FeaturedPerson {
/**
* #var integer
*
* #ORM\Column(name="id", type="integer", nullable=false)
* #ORM\Id
* #ORM\GeneratedValue(strategy="IDENTITY")
*/
private $id;
/**
* #var string
*
* #ORM\Column(name="content", type="string", length=2500, nullable=false)
*/
private $content;
/**
* #var \DateTime
*
* #ORM\Column(name="date_updated", type="datetime")
*/
private $dateUpdated;
/**
* #var bool
*
* #ORM\Column(name="shown_on_homepage", type="boolean", nullable=false)
*/
private $isShownOnHomepage;
//...
public function getIsShownOnHomepage() {
return $this->isShownOnHomepage;
}
public function setIsShownOnHomepage($isShownOnHomepage) {
$this->isShownOnHomepage = $isShownOnHomepage;
return $this;
}
}
And for the Controller I've:
$featured = new FeaturedPerson();
$featured->setContent('Test content.');
$featured->setDateUpdated('01/02/2013.');
$featured->setIsShownOnHomepage(TRUE);
$em = $this->getDoctrine()->getManager();
$em->persist($featured);
$em->flush();
It does add the new row, but the one that had a shown_on_homepage set to 1 still has it. I've researched but I couldn't find a way to achieve this, I hope you can help me.

Answer 1

You could execute a query prior to your existing code in your controller:
$queryBuilder = $this->getDoctrine()->getRepository('YourBundleName:FeaturedPerson')->createQueryBuilder('qb');
$result = $queryBuilder->update('YourBundleName:FeaturedPerson', 'd')
->set('d.isShownOnHomepage', $queryBuilder->expr()->literal(0))
->where('d.isShownOnHomepage = :shown')
->setParameter('shown', 1)
->getQuery()
->execute();
Change 'YourBundleName' to your bundle name.