increments('id'); }); Schema::create('posts', function (Blueprint $table) { $table->increments('post_id'); $table->unsignedInteger('user_id'); }); Schema::create('videos', function (Blueprint $table) { $table->increments('video_id'); }); Schema::create('comments', function (Blueprint $table) { $table->increments('id'); $table->string('commentable_type'); $table->integer('commentable_id'); }); $user = User::create(); $post = tap((new Post)->user()->associate($user))->save(); $video = Video::create(); (new Comment)->commentable()->associate($post)->save(); (new Comment)->commentable()->associate($video)->save(); } public function testLazyEagerLoading() { $comments = Comment::all(); DB::enableQueryLog(); $comments->load('commentable'); $this->assertCount(3, DB::getQueryLog()); $this->assertTrue($comments[0]->relationLoaded('commentable')); $this->assertTrue($comments[0]->commentable->relationLoaded('user')); $this->assertTrue($comments[1]->relationLoaded('commentable')); } } class Comment extends Model { public $timestamps = false; public function commentable() { return $this->morphTo(); } } class Post extends Model { public $timestamps = false; protected $primaryKey = 'post_id'; protected $with = ['user']; public function user() { return $this->belongsTo(User::class); } } class User extends Model { public $timestamps = false; } class Video extends Model { public $timestamps = false; protected $primaryKey = 'video_id'; }