Question

I am having issues saving the selections made in a entity form field with multiple=true.

The selections come through when $form->bindRequest($request) is called but don’t persist in the database when flush is called.

Here is the relevant controller code:

$news_item = new News();

$form = $this->createFormBuilder($news_item)
  ->add('products', 'entity', 
        array('class' => 'AcmeDemoBundle:Product',
      'multiple' => TRUE))
  ->getForm();

$request = $this->getRequest();

if($request->getMethod() == "POST") {
  $form->bindRequest($request);
  if($form->isValid()) {
    $this->em->persist($news_item);
    $this->em->flush();
  }
}

I have checked the $news_item object after $form->isValid() and a count($news_item->getProducts()) returns the correct number of items. The $news_item itself is saved in the DB but the ManyToMany relationship isn’t being saved.

Here are the entities for reference (clipped for brevity):

/**
 * @ORM\Entity
 * @ORM\Table(name="Product")
 */
class Product {
  /*
   * @ORM\Id @ORM\Column(type="integer")
   */
  protected $id;

  /**
   * @ORM\ManyToMany(targetEntity="News", inversedBy="products")
   */
  protected $news_items = null;

  public function __construct() {
    $this->news_items = new ArrayCollection();
  }

}

/**
 * @ORM\Entity
 * @ORM\Table(name="News")
 */
class News {
  /**
   * @ORM\Id @ORM\Column(type="integer") @ORM\GeneratedValue
   */
  protected $id;

  /** 
   * @ORM\ManyToMany(targetEntity="Product", mappedBy="news_items")
   */
  protected $products = null;

  public function __construct() {
    $this->products = new ArrayCollection();
  }
}

Answer 1

I think you are missing $product->addNewsItem($news_item) and $news_item->addProduct($product) in your code this because in bi-directional associations (seems your case) you have to update the fields on both sides.

To avoid this you can set the cascade option on both sides of the association:

@ORM\ManyToMany(targetEntity="Product", mappedBy="news_items",
   cascade={"persist", "remove"})

This way your code will work. You can choose the appropriate cascade options looking at here.