Doctrine Single Table Inheritance and bidirectional OneToMany: columns not being generated - doctrine-orm

Question

The data model:
The entities:
Pet:
/**
* #ORM\Entity
* #ORM\Table(name="pet")
* #ORM\InheritanceType("JOINED")
* #ORM\DiscriminatorColumn(name="pet_type", type="string")
*/
abstract class Pet
{
/**
* #ORM\Id
* #ORM\Column(type="integer")
*/
protected $id;
/**
* #ORM\OneToMany(
* targetEntity="Collar",
* mappedBy="pet",
* cascade={"persist", "remove"},
* orphanRemoval=TRUE
* )
* #ORM\JoinColumn(name="collars", referencedColumnName="id")
*/
protected $collars;
/**
* #ORM\Column(type="integer")
*/
protected $age;
}
Cat:
/**
* #ORM\Entity
* #ORM\Table(name="cat")
*/
class Cat extends Pet
{
/**
* #ORM\Column(type="decimal")
*/
private $purringDecibels;
}
Collar:
/**
* #ORM\Entity
* #ORM\Table(name="collar")
*/
class Collar
{
/**
* #ORM\Id
* #ORM\Column(name="id", type="integer")
*/
private $id;
/**
* #ORM\ManyToOne(targetEntity="Pet", inversedBy="collars")
* #ORM\JoinColumn(name="pet", referencedColumnName="id", nullable=false)
*/
private $pet;
/**
* #ORM\Column(type="string", length="255")
*/
private $color;
}
The problem:
The generated tables are fine except pet: It lacks the collars column, therefore the bidirectionality is broken. While the pet ids do get stored on the collar table, I cannot fetch collars from a pet (i.e. $pet->getCollars()) as it always returns an empty collection.
What am I missing out here?
PS:
The validate console helper says all (mapping & db) is OK.
Yes, I have my getters and setters (i.e. adders and removers)
I know about the infamous performance impact of the combination between a CTI and this kind of relationship.

Answer 1

You do not need to have a "collars" column on the pet table. It is a one-to-many relationship, so the only table that need to "know" about pets are the collar table.
A bidirectional relationship does not mean you need two columns on two tables.
Your map seems correct.