Using EntityRepository::findBy() with Many-To-Many relations will lead to a E_NOTICE in Doctrine

Question

For a Symfony2 project I had to create a relationship between a blog post and so called platforms. A platform defines a specific filter based on the domain you use to view the site. For example: If you join the site by url first-example.com, the site will only provide blog posts, which are connected to this specific platform. To do so, I created two entities Post and Platform. Afterwards I mapped them together with a Many-To-Many relationship. I'm trying to retrieve data via this Many-To-Many relationship from the builtin function `findBy()` in Doctrines' `EntityRepository`. ``` // every one of these methods will throw the same error $posts = $postRepo->findBy(array('platforms' => array($platform))); $posts = $postRepo->findByPlatforms($platform); $posts = $postRepo->findByPlatforms(array($platform)); ``` Where `$postRepo` is the correct Repository for the `Post` entity and `$platform` an existing `Platform` object. Either way: I end up getting the following error: ``` ErrorException:…

Accepted Answer

Another way, maybe a bit OO/cleaner without using IDs:

```
public function getPosts(Platform $platform)
{
    $qb = $this->createQueryBuilder("p")
        ->where(':platform MEMBER OF p.platforms')
        ->setParameters(array('platform' => $platform))
    ;
    return $qb->getQuery()->getResult();
}
```

A better method name would be `findPostsByPlatform`

Using EntityRepository::findBy() with Many-To-Many relations will lead to a E_NOTICE in Doctrine

Solution

Problem