Array hydration Example

array_hyrdation.php

<?php

namespace Vendor\Prefix\Repository;

use Doctrine\ORM\EntityRepository;

class ProductRepository extends EntityRepository
{
    public function find($id)
    {
        // $em is the entity manager
        $qb = $em->createQueryBuilder();

        $qb
            ->select('product', 'category', 'tag', 'brand')
            // Or SomeBundle:Product if you're on symfony
            ->from('Vendor\Prefix\Entity\Product', 'product')
            // You need to explicitly fetch join all your 
            // associations...and select them
            ->leftJoin('product.Brand', 'brand')
            ->leftJoin('product.Tags', 'tag')
            ->leftJoin('product.Categories', 'category')
            // Use prepared statments...its a good habit
            ->where($qb->expr()->eq('product.ID', ':id'))
            ->setParameter('id', $id)
        ;

        $query = $qb->getQuery();

        // Potential Hydration Modes
        // --------------------------------
        // Doctrine\ORM\Query::HYDRATE_OBJECT
        // Doctrine\ORM\Query::HYDRATE_ARRAY 
        // Doctrine\ORM\Query::HYDRATE_SCALAR
        // Doctrine\ORM\Query::HYDRATE_SINGLE_SCALAR
        // Doctrine\ORM\Query::HYDRATE_SIMPLEOBJECT

        // Hydrate the result as an array to get the requested format
        // When you use array hyrdation doctrine does it according 
        // to your entity graph
        return $query->getResult(Doctrine\ORM\Query::HYDRATE_ARRAY);
    }
}