OneToOne: Support for polymorphic associations

[ihorsamusenko]

Case:
I have plenty of entities in the system. I also have entity_alias table which consist of two fields: alias (pk), entity_id. (NOTE: in my database all the entities have a unique id across the whole database, that is why I do not have entity_type field in entity_alias table).

Goal:
Create a trait which can be used to any entity and which provides an ability to set, get and drop alias for an entity.

Code example:
Alias entity:

/**
 * Class Alias
 *
 * @ORM\Entity()
 * @ORM\Table("entity_alias")
 * @UniqueEntity("entityId")
 */
class Alias
{
    /**
     * @var string
     * @Assert\NotBlank()
     * @ORM\Column(type="bigint", nullable=false)
     */
    private $entityId;
    /**
     * @var string
     *
     * @ORM\Id
     * @ORM\Column(type="string", nullable=false)
     */
    private $alias;

    /**
     * Alias constructor.
     *
     * @param $objectId
     * @param $alias
     */
    public function __construct($objectId, $alias)
    {
        $this->alias = $alias;
        $this->objectId = $objectId;
    }
    /**
     * @return mixed
     */
    public function __toString()
    {
        $sting = $this->alias;
        return (string) $sting;
    }
}

AliasableTrait:

trait AliasableTrait
{
   /**
    * @ORM\OneToOne(targetEntity="Alias", cascade={"persist", "remove"}, orphanRemoval=true)
    * @ORM\JoinColumn(name="id", referencedColumnName="entity_id", onDelete="CASCADE")
    * @var Alias
    */
    protected $alias;
    /**
     * @return string|int
     */
    abstract public function getId();
    /**
     * @param string $alias
     */
    public function setAlias(string $alias)
    {
        $this->alias = new Alias($this->getId(), $alias);
    }
    /**
     * @return string
     */
    public function getAlias() : string
    {
        return (string) $this->alias;
    }
    public function dropAlias()
    {
        $this->alias = null;
    }
}

Right now I am getting Missing value for primary key alias on Alias.

Question:
Is it possible to do?

[malutanpetronel]

did you manage to make it work ?