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[Home](https://www.msaied.com/public) 2. / 3. [Articles](https://www.msaied.com/public/articles) 4. / 5. Eloquent Custom Relations: Polymorphic Pivots, Has-One-Of-Many, and Raw Join Relations Eloquent Custom Relations: Polymorphic Pivots, Has-One-Of-Many, and Raw Join Relations ======================================================================================= Beyond belongsTo and hasMany lies a set of underused Eloquent relation types that eliminate ugly query hacks. This article covers HasOneOfMany, custom intermediate table models, and rolling your own relation class. ![](https://cdn.msaied.com/01M22N44A70A5MC2S599JP0MPH.webp) [Mohamed Said](https://www.msaied.com/public#person) Published 2 Oct 2026 · Updated 2 Oct 2026 · 3 min read ShareCopy linkCopied ![Eloquent Custom Relations: Polymorphic Pivots, Has-One-Of-Many, and Raw Join Relations](https://cdn.msaied.com/728/b96439f5ef5f084b44d736951875f964.png) On this page +1. [Eloquent Custom Relations: HasOneOfMany, Polymorphic Pivots, and Rolling Your Own](#eloquent-custom-relations-hasoneofmany-polymorphic-pivots-and-rolling-your-own) 2. [hasOne of Many: The Right Way to Fetch Latest/Oldest](#codehasonecode-of-many-the-right-way-to-fetch-latestoldest) 3. [Custom Pivot Models for Polymorphic Many-to-Many](#custom-pivot-models-for-polymorphic-many-to-many) 4. [Building a Bespoke Relation Class](#building-a-bespoke-relation-class) 5. [Takeaways](#takeaways) Eloquent Custom Relations: HasOneOfMany, Polymorphic Pivots, and Rolling Your Own --------------------------------------------------------------------------------- Most Laravel codebases reach for `hasMany` + `sortByDesc` + `first()` when they need the *latest* related record. That pattern is fine until you need to eager-load it across 500 parent models. Eloquent ships with better tools — and when those run out, you can build your own relation class. --- `hasOne` of Many: The Right Way to Fetch Latest/Oldest ------------------------------------------------------ Introduced in Laravel 8, `ofMany` variants let you declare a constrained single-record relation that Eloquent can eager-load efficiently. ```php // User model public function latestOrder(): HasOne { return $this->hasOne(Order::class)->latestOfMany(); } public function largestOrder(): HasOne { return $this->hasOne(Order::class)->ofMany('total', 'max'); } // Complex: latest order that is also paid public function latestPaidOrder(): HasOne { return $this->hasOne(Order::class) ->ofMany( ['created_at' => 'max'], fn ($q) => $q->where('status', 'paid') ); } ``` Under the hood Eloquent rewrites this as a self-join subquery, so `User::with('latestPaidOrder')->get()` fires **two** queries total — not N+1. --- Custom Pivot Models for Polymorphic Many-to-Many ------------------------------------------------ When a polymorphic pivot carries extra columns, the default `MorphPivot` is often enough — but you lose casting, events, and custom methods unless you declare an explicit model. ```php // Migration: taggables table with a weight column Schema::create('taggables', function (Blueprint $table) { $table->foreignId('tag_id')->constrained(); $table->morphs('taggable'); $table->unsignedTinyInteger('weight')->default(1); }); // Taggable pivot model class Taggable extends MorphPivot { protected $table = 'taggables'; protected $casts = ['weight' => 'integer']; public function isPromoted(): bool { return $this->weight >= 5; } } // Tag model public function posts(): MorphToMany { return $this->morphedByMany(Post::class, 'taggable') ->using(Taggable::class) ->withPivot('weight'); } ``` Now `$tag->posts->first()->pivot->isPromoted()` works, and pivot observers fire correctly. --- Building a Bespoke Relation Class --------------------------------- Sometimes you need a relation that Eloquent simply does not model — for example, joining on a non-FK expression like `YEAR(orders.created_at) = users.cohort_year`. Extend `Illuminate\Database\Eloquent\Relations\Relation` and implement the four required methods: ```php use Illuminate\Database\Eloquent\Builder; use Illuminate\Database\Eloquent\Collection; use Illuminate\Database\Eloquent\Model; use Illuminate\Database\Eloquent\Relations\Relation; class HasManySameCohortYear extends Relation { public function addConstraints(): void { if (static::$constraints) { $this->query->whereRaw( 'YEAR(orders.created_at) = ?', [$this->parent->cohort_year] ); } } public function addEagerConstraints(array $models): void { $years = collect($models)->pluck('cohort_year')->unique()->values(); $this->query->whereRaw( 'YEAR(orders.created_at) IN (' . $years->map(fn () => '?')->implode(',') . ')', $years->all() ); } public function initRelation(array $models, $relation): array { foreach ($models as $model) { $model->setRelation($relation, $this->related->newCollection()); } return $models; } public function match(array $models, Collection $results, $relation): array { foreach ($models as $model) { $matched = $results->filter( fn ($r) => (int) date('Y', strtotime($r->created_at)) === (int) $model->cohort_year ); $model->setRelation($relation, $matched->values()); } return $models; } public function getResults(): Collection { return $this->query->get(); } } ``` Then expose it from your model: ```php public function cohortOrders(): HasManySameCohortYear { return new HasManySameCohortYear( Order::query(), $this, 'orders.created_at', // foreign key hint (unused here but required by constructor) 'id' ); } ``` `User::with('cohortOrders')->get()` now runs two queries and maps correctly. --- Takeaways --------- - Use `ofMany` variants instead of `hasMany + collection manipulation` whenever you need a single constrained record — it eager-loads efficiently. - Declare explicit `MorphPivot` subclasses when your polymorphic pivot carries domain logic or needs Eloquent events. - Eloquent's `Relation` contract has only four abstract methods; implementing them gives you full eager-loading support for any join shape. - Always implement `addEagerConstraints` with a `whereIn` — never loop and query inside `match`. - [laravel](https://www.msaied.com/public/articles?search=laravel) - [eloquent](https://www.msaied.com/public/articles?search=eloquent) - [database](https://www.msaied.com/public/articles?search=database) - [orm](https://www.msaied.com/public/articles?search=orm) - [php](https://www.msaied.com/public/articles?search=php) Frequently asked questions --------------------------- Does `latestOfMany` work with eager loading, or does it still cause N+1?It fully supports eager loading. Eloquent compiles it into a subquery join, so `Model::with('latestRelation')->get()` issues exactly two SQL queries regardless of result set size. When should I use a custom Relation class versus a scope or raw query?Use a custom Relation class when the association needs to be eager-loaded across collections, reused across multiple models, or composed with other Eloquent features like `withCount`. A scope is fine for single-model queries but cannot be eager-loaded. Can I attach pivot observers to a MorphPivot subclass?Yes. Register the observer in a service provider with `Taggable::observe(TaggableObserver::class)`. Events like `creating`, `updating`, and `deleting` fire as long as you use `attach`/`sync` with the `using()` declaration on the relation. ![Mohamed Said](https://cdn.msaied.com/01M22N44A70A5MC2S599JP0MPH.webp)About the author ---------------- [Mohamed Said](https://www.msaied.com/public#person)Senior Backend Engineer specializing in Laravel, scalable SaaS platforms, APIs, and cloud infrastructure. I build secure, high-performance web applications that help businesses grow. [About](https://www.msaied.com/public#about) [GitHub ↗](https://github.com/EG-Mohamed) [LinkedIn ↗](https://www.linkedin.com/in/msaiedm/) [WhatsApp ↗](https://wa.me/201094619204) [Email Address ↗](mailto:hello@msaied.com) [My CV ↗](https://drive.google.com/file/u/0/d/1MF20IPRJyzfy32mhEutjL5EpSls0w2Q8/view) [Previous articleLaravel Caching Strategies: Tags, Stampede Prevention, and Cache-Aside at Scale](https://www.msaied.com/public/articles/laravel-caching-strategies-tags-stampede-prevention-and-cache-aside-at-scale-2) [Next articleLaravel Octane + FrankenPHP: Request Lifecycle, Shared State, and Safe Singleton Patterns](https://www.msaied.com/public/articles/laravel-octane-frankenphp-request-lifecycle-shared-state-and-safe-singleton-patterns) On this page ------------- 1. [Eloquent Custom Relations: HasOneOfMany, Polymorphic Pivots, and Rolling Your Own](#eloquent-custom-relations-hasoneofmany-polymorphic-pivots-and-rolling-your-own) 2. [hasOne of Many: The Right Way to Fetch Latest/Oldest](#codehasonecode-of-many-the-right-way-to-fetch-latestoldest) 3. [Custom Pivot Models for Polymorphic Many-to-Many](#custom-pivot-models-for-polymorphic-many-to-many) 4. [Building a Bespoke Relation Class](#building-a-bespoke-relation-class) 5. [Takeaways](#takeaways) ### Have a technical challenge? Tell me what you’re building. I reply within two working days. 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