Laravel Eloquent ORM

Agent Workflow (MANDATORY)

Before ANY implementation, launch in parallel:

1. fuse-ai-pilot:explore-codebase - Check existing models, relationships
2. fuse-ai-pilot:research-expert - Verify latest Eloquent docs via Context7
3. mcp__context7__query-docs - Query specific patterns (casts, scopes)

After implementation, run fuse-ai-pilot:sniper for validation.

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Overview

Eloquent is Laravel's ActiveRecord ORM implementation. Models represent database tables and provide a fluent interface for queries.

Feature	Purpose
Models	Table representation with attributes
Relationships	Define connections between models
Query Scopes	Reusable query constraints
Casts	Attribute type conversion
Events/Observers	React to model lifecycle
Factories	Generate test data

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Critical Rules

1. Always eager load relationships - Prevent N+1 queries
2. Use scopes for reusable queries - Don't repeat WHERE clauses
3. Cast attributes properly - Type safety for dates, arrays, enums
4. No business logic in models - Keep models slim
5. Use factories for testing - Never hardcode test data

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Decision Guide

Relationship Type

What's the cardinality?
├── One-to-One → hasOne / belongsTo
├── One-to-Many → hasMany / belongsTo
├── Many-to-Many → belongsToMany (pivot table)
├── Through another → hasOneThrough / hasManyThrough
└── Polymorphic?
    ├── One-to-One → morphOne / morphTo
    ├── One-to-Many → morphMany / morphTo
    └── Many-to-Many → morphToMany / morphedByMany

Performance Issue

What's the problem?
├── Too many queries → Eager loading (with)
├── Memory exhaustion → chunk() or cursor()
├── Slow queries → Add indexes, select columns
├── Repeated queries → Cache results
└── Large inserts → Batch operations

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Reference Guide

Concepts (WHY & Architecture)

Topic	Reference	When to Consult
Models	models.md	Model config, fillable, conventions
Basic Relations	relationships-basic.md	HasOne, HasMany, BelongsTo
Many-to-Many	relationships-many-to-many.md	Pivot tables, attach/sync
Advanced Relations	relationships-advanced.md	Through, dynamic relations
Polymorphic	relationships-polymorphic.md	MorphTo, MorphMany
Eager Loading	eager-loading.md	N+1 prevention, with()
Scopes	scopes.md	Local, global, dynamic
Casts	casts.md	Type casting, custom casts
Accessors/Mutators	accessors-mutators.md	Attribute transformation
Events/Observers	events-observers.md	Lifecycle hooks
Soft Deletes	soft-deletes.md	Recoverable deletion
Collections	collections.md	Eloquent collection methods
Serialization	serialization.md	toArray, toJson, hidden
Factories	factories.md	Test data generation
Performance	performance.md	Optimization techniques
API Resources	resources.md	JSON transformation
Transactions	transactions.md	Atomic operations, rollback
Pagination	pagination.md	paginate, cursor, simplePaginate
Aggregates	aggregates.md	count, sum, withCount, exists
Batch Operations	batch-operations.md	insert, upsert, mass update
Query Debugging	query-debugging.md	toSql, dd, DB::listen

Templates (Complete Code)

Template	When to Use
ModelBasic.php.md	Standard model with scopes
ModelRelationships.php.md	All relationship types
ModelCasts.php.md	Casts and accessors
Observer.php.md	Complete observer
Factory.php.md	Factory with states
Resource.php.md	API resource
EagerLoadingExamples.php.md	N+1 prevention

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Quick Reference

Basic Model

class Post extends Model
{
    protected $fillable = ['title', 'content', 'author_id'];

    protected function casts(): array
    {
        return [
            'published_at' => 'datetime',
            'metadata' => 'array',
        ];
    }

    public function author(): BelongsTo
    {
        return $this->belongsTo(User::class);
    }
}

Eager Loading

// ✅ Good - 2 queries
$posts = Post::with('author')->get();

// ❌ Bad - N+1 queries
$posts = Post::all();
foreach ($posts as $post) {
    echo $post->author->name;
}

Query Scopes

#[Scope]
protected function published(Builder $query): void
{
    $query->whereNotNull('published_at');
}

// Usage: Post::published()->get();

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Best Practices

DO

• Use

  $fillable

  for mass assignment protection
• Eager load relationships with

  with()

• Use scopes for reusable query logic
• Cast dates, arrays, and enums
• Use factories in tests

DON'T

• Put business logic in models
• Lazy load in loops (N+1)
• Use

  $guarded = []

  in production
• Query in accessors/mutators
• Forget foreign keys in

  with()

  columns