Symfony4 extending entity does not add Entity column to database schema - symfony

Question

I am developing symfony 4.2 application. I have entity Meal and OrderItem. OrderItem should have all Meal entity properties + few of it's own. The problem is with ManyToOne relationship column. It is not added to order_item table.
https://www.doctrine-project.org/projects/doctrine-orm/en/2.6/reference/inheritance-mapping.html
I tried following "Class Table Inheritance" and "Mapped Superclasses". Example from "Mapped Superclasses" does not add $mappedRelated1 to EntitySubClass . And example from "Class Table Inheritance" removes every other extended field from Meal class and adds some kind of "dtype" column to Meal table.
/**
* #ORM\Entity(repositoryClass="App\Repository\OrderItemRepository")
*/
class OrderItem extends Meal
{
/**
* #ORM\ManyToOne(targetEntity="App\Entity\Order", inversedBy="orderItems")
*/
private $order;
/**
* #ORM\Column(type="integer")
* #Assert\NotBlank
* #Assert\Type("string")
*/
private $amount;
}
/**
* #ORM\Entity(repositoryClass="App\Repository\MealRepository")
*/
class Meal
{
/**
* #ORM\Id()
* #ORM\GeneratedValue()
* #ORM\Column(type="integer")
*/
protected $id;
/**
* #ORM\Column(type="string", length=255)
* #Assert\NotBlank
* #Assert\Type("string")
*/
protected $name;
/**
* #ORM\Column(type="float")
* #Assert\NotBlank
* #Assert\Type("float")
*/
protected $price;
/**
* #ORM\Column(type="string", length=255)
* #Assert\Image(
* mimeTypes={"image/jpeg", "image/png"}
* )
*/
protected $image;
/**
* #ORM\ManyToOne(targetEntity="App\Entity\Menu", inversedBy="meals")
*/
protected $menu;
}
I expect to have "menu_id" column in "order_item" table, which would have relation to Menu entity.
I know that I could copy all the properties from Meal to OrderItem, but that does not sound right.
EDIT:
Both Meal and OrderItem should be able to have it's instance.

Answer 1

menu_id column is already exists in meal
/**
* #ORM\ManyToOne(targetEntity="App\Entity\Menu", inversedBy="meals")
*/
protected $menu;
OrderItem class doesnt need to have just because it is already subclass of meal.
Also you dont need to copy all propertites from Meal to OrderItem.
u can check php extends here

Answer 2

I had the same issue. I used Trait instead of inheritance and the problem was solved.
Your class will be like this
trait MealInfoTrait
{
/**
* #ORM\Column(type="string", length=255)
* #Assert\NotBlank
* #Assert\Type("string")
*/
protected $name;
/**
* #ORM\Column(type="float")
* #Assert\NotBlank
* #Assert\Type("float")
*/
protected $price;
/**
* #ORM\Column(type="string", length=255)
* #Assert\Image(
* mimeTypes={"image/jpeg", "image/png"}
* )
*/
protected $image;
/**
* #ORM\ManyToOne(targetEntity="App\Entity\Menu", inversedBy="meals")
*/
protected $menu;
}
Then, change you Meal class
/**
* #ORM\Entity(repositoryClass="App\Repository\MealRepository")
*/
class Meal
{
use MealInfoTrait;
/**
* #ORM\Id()
* #ORM\GeneratedValue()
* #ORM\Column(type="integer")
*/
protected $id;
}
And do the same with your OrderItem class. Don't forget to add the id for the database.
/**
* #ORM\Entity(repositoryClass="App\Repository\OrderItemRepository")
*/
class OrderItem
{
use MealInfoTrait;
/**
* #ORM\Id()
* #ORM\GeneratedValue()
* #ORM\Column(type="integer")
*/
protected $id;
/**
* #ORM\ManyToOne(targetEntity="App\Entity\Order", inversedBy="orderItems")
*/
private $order;
/**
* #ORM\Column(type="integer")
* #Assert\NotBlank
* #Assert\Type("string")
*/
private $amount;
}