abstract class Animal 
{
    protected $id
}

class Cat extends Animal
{
    private $sound
}

class Sound 
{
    private $id
}

/** @var \Doctrine\ORM\Mapping\ClassMetadata $metadata */
$builder = new \Doctrine\ORM\Mapping\Builder\ClassMetadataBuilder($metadata);
$builder->setTable('animal');
$builder->setSingleTableInheritance();
$builder->setDiscriminatorColumn('kind', 'string', 32);
$builder->createField('id', 'binary')->isPrimaryKey()->build();

/** @var \Doctrine\ORM\Mapping\ClassMetadata $metadata */
$builder = new \Doctrine\ORM\Mapping\Builder\ClassMetadataBuilder($metadata);
$builder->createOneToOne('sound', Sound::class)->fetchLazy()->addJoinColumn('sound_id', 'id', false)->build();

/** @var \Doctrine\ORM\Mapping\ClassMetadata $metadata */
$builder = new \Doctrine\ORM\Mapping\Builder\ClassMetadataBuilder($metadata);
$builder->setTable('sound');
$builder->createField('id', 'binary')->isPrimaryKey()->build();