Eloquent Best Practices Query Optimization Always Eager Load Relationships // ❌ N+1 Query Problem $posts = Post::all(); foreach ($posts as $post) { echo $post->user->name; // N additional queries }

// ✅ Eager Loading $posts = Post::with('user')->get(); foreach ($posts as $post) { echo $post->user->name; // No additional queries }

Select Only Needed Columns // ❌ Fetches all columns $users = User::all();

// ✅ Only needed columns $users = User::select(['id', 'name', 'email'])->get();

// ✅ With relationships $posts = Post::with(['user:id,name'])->select(['id', 'title', 'user_id'])->get();

Use Query Scopes // ✅ Define reusable query logic class Post extends Model { public function scopePublished($query) { return $query->where('status', 'published') ->whereNotNull('published_at'); }

public function scopePopular($query, $threshold = 100)
{
    return $query->where('views', '>', $threshold);
}

}

// Usage $posts = Post::published()->popular()->get();

Relationship Best Practices Define Return Types use Illuminate\Database\Eloquent\Relations\BelongsTo; use Illuminate\Database\Eloquent\Relations\HasMany;

class Post extends Model { public function user(): BelongsTo { return $this->belongsTo(User::class); }

public function comments(): HasMany
{
    return $this->hasMany(Comment::class);
}

}

Use withCount for Counts // ❌ Triggers additional queries foreach ($posts as $post) { echo $post->comments()->count(); }

// ✅ Load counts efficiently $posts = Post::withCount('comments')->get(); foreach ($posts as $post) { echo $post->comments_count; }

Mass Assignment Protection class Post extends Model { // ✅ Whitelist fillable attributes protected $fillable = ['title', 'content', 'status'];

// Or blacklist guarded attributes
protected $guarded = ['id', 'user_id'];

// ❌ Never do this
// protected $guarded = [];

}

Use Casts for Type Safety class Post extends Model { protected $casts = [ 'published_at' => 'datetime', 'metadata' => 'array', 'is_featured' => 'boolean', 'views' => 'integer', ]; }

Chunking for Large Datasets // ✅ Process in chunks to save memory Post::chunk(200, function ($posts) { foreach ($posts as $post) { // Process each post } });

// ✅ Or use lazy collections Post::lazy()->each(function ($post) { // Process one at a time });

Database-Level Operations // ❌ Slow - loads into memory first $posts = Post::where('status', 'draft')->get(); foreach ($posts as $post) { $post->update(['status' => 'archived']); }

// ✅ Fast - single query Post::where('status', 'draft')->update(['status' => 'archived']);

// ✅ Increment/decrement Post::where('id', $id)->increment('views');

Use Model Events Wisely class Post extends Model { protected static function booted() { static::creating(function ($post) { $post->slug = Str::slug($post->title); });

    static::deleting(function ($post) {
        $post->comments()->delete();
    });
}

}

Common Pitfalls to Avoid Don't Query in Loops // ❌ Bad foreach ($userIds as $id) { $user = User::find($id); }

// ✅ Good $users = User::whereIn('id', $userIds)->get();

Don't Forget Indexes // Migration Schema::create('posts', function (Blueprint $table) { $table->id(); $table->foreignId('user_id')->constrained()->index(); $table->string('slug')->unique(); $table->string('status')->index(); $table->timestamp('published_at')->nullable()->index();

// Composite index for common queries
$table->index(['status', 'published_at']);

});

Prevent Lazy Loading in Development // In AppServiceProvider boot method Model::preventLazyLoading(!app()->isProduction());

Checklist Relationships eagerly loaded where needed Only selecting required columns Using query scopes for reusability Mass assignment protection configured Appropriate casts defined Indexes on foreign keys and query columns Using database-level operations when possible Chunking for large datasets Model events used appropriately Lazy loading prevented in development

eloquent-best-practices

安装