Doctrine2 ArrayCollection count Distinct unique

Question

I'm facing a litte trouble with an ArrayCollection Count. I don't know if it is possible to do what I want.

I have 2 entities:

class Instancia{
    /**
    * @ORM\Column(name="name", type="string")
    */
    private $name;

    /**
    * @ORM\ManyToOne(targetEntity="App\Entity\Resultado", inversedBy="instancias", fetch="EXTRA_LAZY")
    * @ORM\JoinColumn(name="resultado", referencedColumnName="id")
    */
    private $resultado;
}
        
class Resultado{
    public function __construct() {
         $this->instancias = new ArrayCollection();
    }
    
    /**
    * @ORM\OneToMany(targetEntity="App\Entity\Instancia", mappedBy="resultado", fetch="EXTRA_LAZY")
    */
    private $instancias;
        
    /**
    * @ORM\Column(name="numInstancias", type="integer")
    */
    private $numInstancia;
    
    function setNumInstancias(){
         $this->numInstancias = $this->instancias->count(); /*return the count of all instancias*/
         /* 1) Want to count with a Distinct instancias->name*/
         /* 2)or want to count with a substr filter in the instancias->name*/
    }
}

What I need is that Resultado->numInstancias count do a distinct by the field name in the Instancia Entity.

In a Repository it would by like the following, but I need to do in the Entity

$qb = $em->createQueryBuilder();
   $qb->select('COUNT(I)')
      ->from('App\Entity\Instancia', 'I')
      ->where('I.resultado = xxx')
      ->groupBy('I.name');

Thanks for your help!!

Answer 1

Yes, this is possible. You can write a function that counts the Instancias by filtering them. Not sure exactly how everything you have is set up so some changes might be required:

public function countInstancias()
{
    return count($this->getInstnacias()->filter(function (Instancia $i) {
        return $i->getName() === 'some name';
    }));
}

Put this in your Resultado entity. I use something similar to get users from certain groups.