Symfony2多个关系还保存现有的相关实体

Question

我在Symfony2.8上遇到了一个多实体关系的问题。我有实体旅行，它可以由许多经验实体组成。

以下是我的旅行定义：

namespace MyBundle\Entity;

use Doctrine\ORM\Mapping as ORM;
use Knp\DoctrineBehaviors\Model as ORMBehaviors;
use Symfony\Component\Validator\Constraints as Assert;

/**
 * Trip
 *
 * @ORM\Table(name="trip")
 * @ORM\Entity(repositoryClass="MyBundle\Repository\TripRepository")
 * @ORM\HasLifecycleCallbacks
 */
class Trip
{
    use ORMBehaviors\Timestampable\Timestampable;
    /**
     * @var int
     *
     * @ORM\Column(name="id", type="integer")
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     */
    private $id;    

    // other fields

    /**
     * @ORM\ManyToMany(targetEntity="MyBundle\Entity\Experience", inversedBy="trips")
     * @ORM\JoinTable(name="experience_trip",
     *  joinColumns={
     *     @ORM\JoinColumn(name="trip_id", referencedColumnName="id")
     *  },
     *  inverseJoinColumns={
     *     @ORM\JoinColumn(name="experience_id", referencedColumnName="id")
     *  }
     * )
     */
    private $experiences;

    /**
     * Constructor
     */
    public function __construct()
    {
        $this->experiences = new \Doctrine\Common\Collections\ArrayCollection();
    }

    // other setters and getters

    /**
     * Add experience
     *
     * @param \MyBundle\Entity\Experience $experience
     *
     * @return Trip
     */
    public function addExperience(\MyBundle\Entity\Experience $experience)
    {
        $this->experiences[] = $experience;

        return $this;
    }

    /**
     * Remove experience
     *
     * @param \MyBundle\Entity\Experience $experience
     */
    public function removeExperience(\MyBundle\Entity\Experience $experience)
    {
        $this->experiences->removeElement($experience);
    }

    /**
     * Get experiences
     *
     * @return \Doctrine\Common\Collections\Collection
     */
    public function getExperiences()
    {
        return $this->experiences;
    }

}

另一方面，我有经验实体：

namespace MyBundle\Entity;

use Doctrine\ORM\Mapping as ORM;
use Knp\DoctrineBehaviors\Model as ORMBehaviors;
use Symfony\Component\Validator\Constraints as Assert;

/**
 * Experience
 *
 * @ORM\Table(name="experience")
 * @ORM\Entity(repositoryClass="MyBundle\Repository\ExperienceRepository")
 */
class Experience
{

    use ORMBehaviors\Translatable\Translatable;
    use ORMBehaviors\Timestampable\Timestampable;


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

    /**
     * @ORM\ManyToMany(targetEntity="MyBundle\Entity\Trip", mappedBy="experiences")
     */
    private $trips;

    // other fields

    /**
     * Constructor
     */
    public function __construct()
    {
        $this->trips = new \Doctrine\Common\Collections\ArrayCollection();
    }

    // other setters and getters

    /**
     * Add trip
     *
     * @param \MyBundle\Entity\Trip $trip
     *
     * @return Experience
     */
    public function addTrip(\MyBundle\Entity\Trip $trip)
    {
        $this->trips[] = $trip;

        return $this;
    }

    /**
     * Remove trip
     *
     * @param \MyBundle\Entity\Trip $trip
     */
    public function removeTrip(\MyBundle\Entity\Trip $trip)
    {
        $this->trips->removeElement($trip);
    }

    /**
     * Get trips
     *
     * @return \Doctrine\Common\Collections\Collection
     */
    public function getTrips()
    {
        return $this->trips;
    }
}

在控制器中，用户可以生成一个新的行程，将对象置于会话中以调用它，直到真正的关联。

/**
 * @Route("/add-experience", name="add_experience")
 */
public function addExperienceAction(Request $request)
{
    $experienceId = $request->query->get('experience');
    $em = $this->getDoctrine()->getManager();

    $experience = $em->getRepository('MyBundle:Experience')->find($experienceId);
    if (!$experience || !get_class($experience) == 'MyBundle:Experience') {
        $response = array("message" => "Experience not found", "success" => false);

        return new Response(json_encode($response));
    }

    $session = $request->getSession();
    $trip = $session->get('trip');
    // This service only construct parameters
    $searchParameters = $this->get('mybundle.search')->buildSearchParameters();
    if (!$trip) {
        $trip = new Trip();
        $trip->setStartDate($searchParameters['startDate']);
        $trip->setEndDate($searchParameters['endDate']);
    }

    $trip->addExperience($experience);
    $trip->setClient($this->getUser()); /** user can be null */
    $em->persist($trip);
    $em->flush();

    $session->set('trip', $trip);

    $response = array("message" => "Experience n.$experienceId added correctly", "success" => true);

    return new Response(json_encode($response));
}

问题。在第一次通话时，它就像一个魔咒，添加experience\u trip条目，一切正常。在第二次调用时，具有不同经验的trip persisting正在寻找经验实体上的级联，抛出错误：

通过关系“MyBundle\entity\Trip#experiences”找到了一个新实体，该关系未配置为级联实体的持久化操作：。要解决此问题，请对此未知实体显式调用EntityManager#persist（），或在映射中配置cascade persist此关联，例如@manytone（..，cascade={“persist”}）。

这是因为试图添加一个新的体验实体，事实上，由于字段的唯一性，使用级联{“persist”}在体验复制上生成一个sql异常。

Sonata TripAdmin类可以正确管理相同的模型，而无需尝试在旅行持续时添加新的体验，而无需避免创建体验旅行实体。在experience_trip表中，我可以正确地看到正确的关联。

为什么要保存行程，第二次尝试插入新的体验？

提前谢谢，对不起我的英语。

Answer 1

我自己找到了解决方案，也感谢这条评论。

由于某种原因，会话中的实体已分离，并且不是有效的实体。所以，坚持尝试再次添加它。