为连接的doctrine 2集合实现getter

Question

I'm trying to create simple getter methods in original entity for specific item in doctrine collection of joined entity.

Main entity looks something like this:

class Product
{
/**
 * @var integer
 *
 * @ORM\Column(name="id", type="integer")
 * @ORM\Id
 * @ORM\GeneratedValue(strategy="AUTO")
 */
private $id;

...

/**
 * @ORM\OneToMany(targetEntity="File", mappedBy="product")
 */
private $files;

}

And joined entity:

class PrankFile
{
/**
 * @var integer
 *
 * @ORM\Column(name="id", type="integer")
 * @ORM\Id
 * @ORM\GeneratedValue(strategy="AUTO")
 */
private $id;

/**
 * @ORM\ManyToOne(targetEntity="Product", inversedBy="files")
 * @ORM\JoinColumn(name="product_id", referencedColumnName="id", onDelete="CASCADE")
 */
protected $product;

/**
 * @var string
 *
 * @ORM\Column(name="type", type="string", length=16)
 */
private $type;  

...

My DQL in repository class is very simple:

    return $this->getEntityManager()
        ->createQuery('SELECT p, f FROM AppProductBundle:Product p INNER JOIN p.files f ORDER BY p.created DESC')
        ->setMaxResults($limit)
        ->getResult();

In files entity type field tells me what kind of a file is it (image, sound, video, demo etc...) Problem comes when I wish to print out a list of all products and display image next to product details, I would hate to loop through product files for each product displayed.

Is it possible to create some simple getter on product entity to fetch file of certain type? Or maybe it would be better to create more complex DQL query for this, again how to do this?

I can't just fetch image record from files in DQL because I need all files for certain products.

Any help with this would be most welcome.

Answer 1

You can filter directly on collections using the filter api. If the collection is not loaded already Doctrine will apply your filter on a SQL level, giving you max performance. In case the collection is already eager loaded Doctrine will filter the ArrayCollection in memory.

use Doctrine\Common\Collections\Criteria;

class Product
{
    public function getFilesByType($type)
    {
        $criteria = Criteria::create()
            ->where(Criteria::expr()->eq("type", $type))
        return $this->files->matching($criteria);
    }
}