CODEWITHSUNDEEP
doctrinedql
Godineau Félicie
Godineau Félicie

Reputation: 438

DQL join two joined tables from different tables

I know the title isn't very clear, but I will try to better explain my problem here. I have 3 Doctrine entities : A, B and C

class A {        class B {            class C {
  $id;             $id;                 $id;
  ManyToMany       ManyToMany         }
  $C;              $C; 
}                }

I'm trying to know if an object A and an object B have at least one same C.

The many to many relations gives me table like :

table AC {          table BC {
   A_id;               B_id;
   C_id;               C_id;
}                    }

I know that I can't use these tables in DQL but what I want to do can be done in SQL. It would give :

SELECT COUNT(A.id) FROM AC INNER JOIN BC 
ON AC.C_id = BC.C_id
WHERE BC.B_id=1217 AND AC.A_id=185

Upvotes: 1

Views: 884

Answers (1)

Matěj Račinský
Matěj Račinský

Reputation: 1804

You will need to make the many to many association bidirectional, so entities will look like this:

<?php

namespace App\Model;

use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\ORM\Mapping as ORM;

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

    /**
     * @var ArrayCollection|C[]
     * @ORM\ManyToMany(targetEntity="C", inversedBy="as")
     */
    private $cs;
}

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

    /**
     * @var ArrayCollection|C[]
     * @ORM\ManyToMany(targetEntity="C", inversedBy="bs")
     */
    private $cs;
}

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

    /**
     * @var ArrayCollection|A[]
     * @ORM\ManyToMany(targetEntity="A", mappedBy="cs")
     */
    private $as;

    /**
     * @var ArrayCollection|A[]
     * @ORM\ManyToMany(targetEntity="B", mappedBy="cs")
     */
    private $bs;

}

And then you can query the C class with conditional join on A and B entities, by this DQL query:

    $query = $this->entityManager->createQuery("SELECT count(c.id) FROM C::class c INNER JOIN c.as a WITH a.id = :a_id INNER JOIN c.bs b WITH b.id = :b_id")
        ->setParameter('a_id', 185)
        ->setParameter('b_id', 1217);
    $result = $query->getSingleScalarResult();

Upvotes: 1

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