<?php

namespace FrontEndBundleEntity;

use DoctrineORMMapping as ORM;

/**
 * MarcaAuto
 *
 * @ORMTable(name="marcas_auto")
 * @ORMEntity(repositoryClass="FrontEndBundleRepositoryMarcaAutoRepository")
 */
class MarcaAuto
{
    /**
     * @var int
     *
     * @ORMColumn(name="id", type="integer")
     * @ORMId
     * @ORMGeneratedValue(strategy="AUTO")
     * @ORMOneToMany(targetEntity="ModeloAuto", mappedBy="idMarca")
     */
    private $id;


    /**
     * @ORMColumn(type="string", length=100)
     */
    private $marca;

<?php

namespace FrontEndBundleEntity;

use DoctrineORMMapping as ORM;

/**
 * ModeloAuto
 *
 * @ORMTable(name="modelos_auto")
 * @ORMEntity(repositoryClass="FrontEndBundleRepositoryModeloAutoRepository")
 */
class ModeloAuto {

    /**
     * @var int
     *
     * @ORMColumn(name="id", type="integer")
     * @ORMId
     * @ORMGeneratedValue(strategy="AUTO")
     */
    private $id;

    /**
     * @var int
     * @ORMColumn(name="id_marca", type="integer")
     * @ORMManyToOne(targetEntity="MarcaAuto", inversedBy="id")
     * @ORMJoinColumn(name="id_marca", referencedColumnName="id")
     */
    private $idMarca;

$em = $this->getDoctrine()->getManager();
        $query = $em->createQuery(
                'SELECT a
                FROM FrontEndBundle:MarcaAuto a
                LEFT JOIN a.id
                ORDER BY a.marca ASC'
        );

        $marcasVehiculos = $query->getResult();