OneToMany relationship not persisting along with new entities

Question

I'm facing some issue when I try to persist a collection of entities using a symfony form. I followed the official documentation but I can't make it work becouse of this error: ``` Entity of type ProductItem has identity through a foreign entity Product, however this entity has no identity itself. You have to call EntityManager#persist() on the related entity and make sure that an identifier was generated before trying to persist ProductItem. In case of Post Insert ID Generation (such as MySQL Auto-Increment or PostgreSQL SERIAL) this means you have to call EntityManager#flush() between both persist operations. ``` I have to entities linked with a OneToMany relation: Product ``` /** * @ORM\Column(name="id", type="integer", nullable=false) * @ORM\Id * @ORM\GeneratedValue(strategy="IDENTITY") */ protected $id; /** * @ORM\OneToMany(targetEntity="ProductItem", mappedBy="product",cascade={"persist"}) */ protected $items; ``` And ProductItem ``` /** * @ORM\Id() * @ORM\ManyToOne(targetEntity…

Accepted Answer

I had exact same problem last week, here is a solution I found after some reading and testing.

The problem is your Product entity has cascade persist (which is usually good) and it first try to persist `ProductItem` but `ProductItem` entities cannot be persisted because they require Product to be persisted first and its ID (Composite key (product, item).

There are 2 options to solve this:

1st I didn't use it but you could simply drop a composite key and use standard id with foreign key to the `Product`

2nd - better This might look like hack, but trust me this is the best what you can do now. It doesn't require any changes to the DB structure and works with form collections without any problems.

Code fragment from my code, article sections have composite key of (article_id, random_hash). Temporary set one to many reference to an empty array, persist it, add you original data and persist (and flush) again.

```
    if ($form->isValid())
    {
        $manager = $this->getDoctrine()->getManager();

$articleSections = $article->getArticleSections();
        $article->setArticleSections(array());  // this won't trigger cascade persist
        $manager->persist($article);
        $manager->flush();

$article->setArticleSections($articleSections);
        $manager->persist($article);
        $manager->flush();
```

OneToMany relationship not persisting along with new entities

Solution

Problem