Get models filtered on related attributes

models-filtered-by-related-attributes

<?php
/*
These are some examples of how you can retrieve models filtered by 
some criteria on related models. For example, using the following set
of tables and relations, you can get all user profiles for users who
have a Member role.

Users ∞ <-> ∞ Roles
Users 1 -> ∞ Profiles
Profiles 1 -> ∞ PortfolioItems

In Laravel 5.5+ there are a couple of ways to do this. Speed and internal
efficiency aside, I prefer this first method. It assumes you have a 
belongsTo() relation on your Profile model called 'user' that returns
the User model for the current Profile. This also assumes you have a 
belongsToMany() relation on your User model called 'roles' that returns
the all the Role models for which there is a relation.

Notes:
    - I have left out namespaces for clarity
 */

class Role {
    public function users() {
        return $this->belongsToMany('User');
    }
}

class User {
    public function roles() {
        return $this->belongsToMany('Role');
    }

    public function profiles() {
        return $this->hasMany('Profile');
    }
}

class Profile {
    public function user() {
        return $this->belongsTo('User');
    }

    public function portfolioItems() {
        return $this->hasMany('PortfolioItem');
    }

    public function scopeProfilesOfMembers ( $query ) {
        return $query->whereHas('user', function( $userquery ) {
            $userquery->whereHas('roles', function( $rolesquery ) {
                $rolesquery->where('name', 'Member');
            });
        });
    }
}

class PortfolioItem {
    public function roles() {
        return $this->belongsTo('Profile');
    }
}