Abstract Class for Doctrine entity

Question

I am trying to make an abstract class for my entities involving general fields like created_at and updated_at values:

<?php
namespace AppBundle;

use Doctrine\ORM;

abstract class Model {

    /**
     * @var \DateTime $created_at
     *
     * @ORM\Column(type="datetime")
     */
    private $created_at;

    /**
     * @var \DateTime $updated_at
     *
     * @ORM\Column(type="datetime")
     */
    private $updated_at;

}

Then, I extend my class:

<?php
namespace AppBundle\Entity;

use AppBundle\Model;

/**
 * Entity
 *
 * @ORM\Table()
 * @ORM\Entity(repositoryClass="RB\ProductsBundle\Entity\ProductRepository")
 */
class Entity extends Model
{
    /**
     * @var integer
     *
     * @ORM\Column(name="id", type="integer")
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     */
    private $id;

    /**
     * @var string
     *
     * @ORM\Column(name="name", type="string", length=255, nullable=true)
     */
    private $name;
}

The problem is: When I make a php app/console doctrine:schema:update --dump-sql, it doesn't recognize the Model fields. How can I change that? Should I use a trait or something like that?

EDIT: I tried to add * @ORM\MappedSuperclass at the top of my abstract class with no luck

Answer 1

The problem is likely to be that your properties in the abstract parent class are defined as private. Change them to protected and it should work.

As an aside, I use traits for this purpose, rather than inheritance, as your entity classes can use multiple traits, but they can only extend one abstract class.