Belongs to pivot table in Laravel 5

Question

Let's say I'm having the following database schema:

dogs and owners are connected with classic belongsToMany. How about the walks table? I'd like to be able to use Eloquent goodies in such kind of relationship:

$dogs = Dog::with('walks')->get();
$walks = Walk::with('dogs')->get();

In theory, I could replace dog_owner_id with two separate columns: dog_id and owner_id. That would make it easy to use Eloquent, but I'd lose some data integrity, because unrelated Dog and Owner could potentially go for a walk (and that's not safe for neither!).

In Walk.php, how should the relations be defined?

public function dog() {
    // return ???;
}

How about Dog.php and Owner.php?

public function walks() {
    // return ???;
}

Answer 1

1- create 4 Models (Walk,Dog,Owner,DogOwner)

2- in Walk.php model

    public function dog()
{

    return $this->hasOneThrough(
        'App\Models\Dog',
        'App\Models\DogOwner',
        'id', // Local key on dog_owner table...
        'id', // Local key on dogs table...
        'dog_owner_id', // Foreign key on walks table...
        'dog_id' // Foreign key on dog_owner table...
    );
}

public function owner()
{

    return $this->hasOneThrough(
        'App\Models\Owner',
        'App\Models\DogOwner',
        'id', // Local key on dog_owner table...
        'id', // Local key on owners table...
        'dog_owner_id', // Foreign key on walks table...
        'owner_id' // Foreign key on dog_owner table...
    );
}       

3- in Dog.php model

   public function walks()
    {
    return $this->hasManyThrough(
        'App\Models\Walk',
        'App\Models\DogOwner',
        'dog_id', // Foreign key on dog_owner table...
        'dog_owner_id', // Foreign key on walks table...
        'id', // Local key on dogs table...
        'id' // Local key on dog_owner table...
    );
    }   

4- in Owner.php model

   public function walks()
   {
    return $this->hasManyThrough(
        'App\Models\Walk',
        'App\Models\DogOwner',
        'owner_id', // Foreign key on dog_owner table...
        'dog_owner_id', // Foreign key on walks table...
        'id', // Local key on owners table...
        'id' // Local key on dog_owner table...
    );
   }