Associate entities with a slug in a common table - doctrine-orm

Question

I am trying to store slugs of different entities in one table.
Suppose we have two entities and tables, 'product' and 'blog', there is also a third table - 'slug' which stores their slugs. The table 'slug' has columns: id, entity (string ('product' or 'blog')), entity_id (id entries from the tables 'product' or 'blog'), slug (string unique).
I am trying to do this in the file App\Entity\Product:
namespace App\Entity;
use Doctrine\ORM\Mapping as ORM;
/**
* #ORM\Entity(repositoryClass="App\Repository\ProductRepository")
* #ORM\Table(name="product")
*/
class Product
{
/**
* #ORM\Id()
* #ORM\GeneratedValue()
* #ORM\Column(type="integer")
*/
private $id;
/**
* #ORM\Column(type="string", length=255)
*/
private $title;
/**
* #ORM\JoinTable(
* name="slug",
* joinColumns={
* #ORM\JoinColumn(name="entity", options={"default":"product"}),
* #ORM\JoinColumn(name="entity_id", referencedColumnName="id"),
* },
* )
*/
private $slug;
This code throw some error:
[Semantical Error] The annotation "#JoinTable" in property App\Entity\Product::$slug was never imported. Did you maybe forget to add a "use" statement for this annotation?
In the entity manager 'product' and 'blog' I need getSlug and setSlug, as well as most likely addSlug - which will add to the table 'slug' the changed value from the variable $title, entity_id id of the entity, as well as in the column entity the line "product" or "blog" depending on which entity will be created

Answer 1

The error is telling you that it does not know what #JoinTable is, try changing this line:
* #JoinTable(
to this:
* #ORM\JoinTable(