TIL: Laravel HasOneThrough model relationship

Context: Participants may earn race credits by volunteering at an event.

By using hasOneThrough() we don't need to add the user.id column on the race_credits table. Simply using hasOneThrough relationship can access the user race credits through the volunteer model.

users
- id
- name

volunteers
- user.id
- event.id

race_credits
- volunteer.id
- event.id

// User.php
public function raceCredits()
{
    return $this->hasOneThrough(
        RaceCredit::class,     
        Volunteer::class
     );
}