Why association is not creating in Doctrine2?

Question

I have 2 entities — NewsItem and Category. It is unidirectional association between this entities: 1 NewsItem has 1 Category, 1 Category has many NewsItem's.

I am trying to create association mapping like in THIS example. What I've tried? My code:

class NewsItem {
    // other fields

    /**
    * @var int
    * @ORM\Column(type="integer")
    * @ORM\ManyToOne(targetEntity="News\Entity\Category")
    */
    protected $category_id;

    // other fiels, getters, setters etc
}

After that, I deleted tables in the database manually and run command orm:schema-tool:update --force in command line. It says that some queries are executed without errors — it's ok. But when I open table Category in HeidiSQL there are no FOREIGN KEYS there. That means that tables are not linked.

What I did wrong?

You can watch full code of this News\Entity\NewsItem entity here: click me. News\Entity\Category entity is here: click me.

Answer 1

you should remove * @ORM\Column(type="integer") as it is conflicting with the many-to-one relation.

Even if it is not the cause of the bug, you should also rename protected $category_id; to protected $category;

Also, your two entities are under the same namespace so it's not necessary to add the related entity's full path. targetEntity="Category" is enough.

Answer 2

You have incorrect mapping information for the Category entity.

Your NewsItem.php file should look like this:

namespace Your\Bundle\Entity;

use Doctrine\ORM\Mapping as ORM;
use Doctrine\ORM\Mapping\JoinColumn;

/**
 * @ORM\Table(name="news_item")
 * @ORM\Entity
 */
class NewsItem {
    /**
     * @var integer
     *
     * @ORM\Column(name="id", type="integer")
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     */
    private $id;

    /**
     * @var Category
     *
     * @ORM\ManyToOne(targetEntity="Category", inversedBy="news_items")
     * @ORM\JoinColumn(name="category_id", referencedColumnName="id")
     */
    private $category;

    // Rest of code omitted.
}

And your Category.php should look like this:

namespace Your\Bundle\Entity;

/**
 * @ORM\Table(name="category")
 * @ORM\Entity
 */
class Category {    
    /**
     * @var integer
     *
     * @ORM\Column(name="id", type="integer")
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     */
    private $id;

    /**
     * @var ArrayCollection
     *
     * @ORM\OneToMany(targetEntity="NewsItem", mappedBy="category")     
     */
    private $news_items;

    public function __construct(){
        $this->news_items = new ArrayCollection();
    }

    // Rest of code omitted.
}